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Chirikian O, Faynus MA, Merk M, Singh Z, Muray C, Pham J, Chialastri A, Vander Roest A, Goldstein A, Pyle T, Lane KV, Roberts B, Smith JE, Gunawardane RN, Sniadecki NJ, Mack DL, Davis J, Bernstein D, Streichan SJ, Clegg DO, Dey SS, Wilson MZ, Pruitt BL. YAP dysregulation triggers hypertrophy by CCN2 secretion and TGFβ uptake in human pluripotent stem cell-derived cardiomyocytes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.03.597045. [PMID: 38895282 PMCID: PMC11185505 DOI: 10.1101/2024.06.03.597045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Hypertrophy Cardiomyopathy (HCM) is the most prevalent hereditary cardiovascular disease - affecting >1:500 individuals. Advanced forms of HCM clinically present with hypercontractility, hypertrophy and fibrosis. Several single-point mutations in b-myosin heavy chain (MYH7) have been associated with HCM and increased contractility at the organ level. Different MYH7 mutations have resulted in increased, decreased, or unchanged force production at the molecular level. Yet, how these molecular kinetics link to cell and tissue pathogenesis remains unclear. The Hippo Pathway, specifically its effector molecule YAP, has been demonstrated to be reactivated in pathological hypertrophic growth. We hypothesized that changes in force production (intrinsically or extrinsically) directly alter the homeostatic mechano-signaling of the Hippo pathway through changes in stresses on the nucleus. Using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), we asked whether homeostatic mechanical signaling through the canonical growth regulator, YAP, is altered 1) by changes in the biomechanics of HCM mutant cardiomyocytes and 2) by alterations in the mechanical environment. We use genetically edited hiPSC-CM with point mutations in MYH7 associated with HCM, and their matched controls, combined with micropatterned traction force microscopy substrates to confirm the hypercontractile phenotype in MYH7 mutants. We next modulate contractility in healthy and disease hiPSC-CMs by treatment with positive and negative inotropic drugs and demonstrate a correlative relationship between contractility and YAP activity. We further demonstrate the activation of YAP in both HCM mutants and healthy hiPSC-CMs treated with contractility modulators is through enhanced nuclear deformation. We conclude that the overactivation of YAP, possibly initiated and driven by hypercontractility, correlates with excessive CCN2 secretion (connective tissue growth factor), enhancing cardiac fibroblast/myofibroblast transition and production of known hypertrophic signaling molecule TGFβ. Our study suggests YAP being an indirect player in the initiation of hypertrophic growth and fibrosis in HCM. Our results provide new insights into HCM progression and bring forth a testbed for therapeutic options in treating HCM.
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Parodi A, Puscas T, Réant P, Donal E, M'Barek Raboudi D, Billon C, Bacher A, El Hachmi M, Wahbi K, Jeunemaître X, Hagège A. Target population for a selective cardiac myosin inhibitor in hypertrophic obstructive cardiomyopathy: Real-life estimation from the French register of hypertrophic cardiomyopathy (REMY). Arch Cardiovasc Dis 2024; 117:427-432. [PMID: 38762345 DOI: 10.1016/j.acvd.2024.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 04/15/2024] [Accepted: 04/15/2024] [Indexed: 05/20/2024]
Abstract
BACKGROUND The efficacy of current pharmacological therapies in hypertrophic cardiomyopathy is limited. A cardiac myosin inhibitor, mavacamten, has recently been approved as a first-in-class treatment for symptomatic hypertrophic obstructive cardiomyopathy. AIMS To assess the profile and burden of cardiac myosin inhibitor candidates in the hypertrophic cardiomyopathy prospective Register of hypertrophic cardiomyopathy (REMY) held by the French Society of Cardiology. METHODS Data were collected at baseline and during follow-up from patients with hypertrophic cardiomyopathy enrolled in REMY by the three largest participating centres. RESULTS Among 1059 adults with hypertrophic cardiomyopathy, 461 (43.5%) had obstruction; 325 (30.7%) of these were also symptomatic, forming the "cardiac myosin inhibitor candidates" group. Baseline features of this group were: age 58±15years; male sex (n=196; 60.3%); diagnosis-to-inclusion delay 5 (1-12)years; maximum wall thickness 20±6mm; left ventricular ejection fraction 69±6%; family history of hypertrophic cardiomyopathy or sudden cardiac death (n=133; 40.9%); presence of a pathogenic sarcomere gene mutation (n=101; 31.1%); beta-blocker or verapamil treatment (n=304; 93.8%), combined with disopyramide (n=28; 8.7%); and eligibility for septal reduction therapy (n=96; 29%). At the end of a median follow-up of 66 (34-106) months, 319 (98.2%) were treated for obstruction (n=43 [13.2%] received disopyramide), 46 (14.2%) underwent septal reduction therapy and the all-cause mortality rate was 1.9/100 person-years (95% confidence interval 1.4-2.6) (46 deaths). Moreover, 41 (8.9%) patients from the initial hypertrophic obstructive cardiomyopathy group became eligible for a cardiac myosin inhibitor. CONCLUSIONS In this cohort of patients with hypertrophic cardiomyopathy selected from the REMY registry, one third were eligible for a cardiac myosin inhibitor.
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Affiliation(s)
- Alessandro Parodi
- Département de cardiologie, hôpital européen Georges-Pompidou, AP-HP, 75015 Paris, France; Università del Piemonte Orientale Amedeo Avogadro, 13100 Vercelli, Italy
| | - Tania Puscas
- Département de cardiologie, hôpital européen Georges-Pompidou, AP-HP, 75015 Paris, France
| | - Patricia Réant
- Département de cardiologie, hôpital Haut-Lévêque, CHU de Bordeaux, université de Bordeaux, Inserm 1045, IHU Lyric, CIC 1401, 33600 Pessac, France
| | - Erwan Donal
- Service de cardiologie, hôpital Pontchaillou, CHU de Rennes, université de Rennes, Inserm, LTSI-UMR 1099, 35000 Rennes, France
| | - Dorra M'Barek Raboudi
- Département de cardiologie, hôpital européen Georges-Pompidou, AP-HP, 75015 Paris, France
| | - Clarisse Billon
- Département de cardiologie, hôpital Haut-Lévêque, CHU de Bordeaux, université de Bordeaux, Inserm 1045, IHU Lyric, CIC 1401, 33600 Pessac, France
| | - Anne Bacher
- Département de cardiologie, hôpital européen Georges-Pompidou, AP-HP, 75015 Paris, France
| | - Mohamed El Hachmi
- Département de génétique, hôpital européen Georges-Pompidou, AP-HP, 75015 Paris, France; Molecular Medicine, La Sapienza University, 00185 Rome, Italy
| | - Karim Wahbi
- Département de génétique, hôpital européen Georges-Pompidou, AP-HP, 75015 Paris, France; Inserm U970, Paris Cardiovascular Research Centre, Université Paris Cité, 75015 Paris, France
| | - Xavier Jeunemaître
- Département de génétique, hôpital européen Georges-Pompidou, AP-HP, 75015 Paris, France; Inserm U970, Paris Cardiovascular Research Centre, Université Paris Cité, 75015 Paris, France
| | - Albert Hagège
- Département de cardiologie, hôpital européen Georges-Pompidou, AP-HP, 75015 Paris, France; Inserm U970, Paris Cardiovascular Research Centre, Université Paris Cité, 75015 Paris, France.
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Spudich JA. One must reconstitute the functions of interest from purified proteins. Front Physiol 2024; 15:1390186. [PMID: 38827995 PMCID: PMC11140241 DOI: 10.3389/fphys.2024.1390186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Accepted: 04/01/2024] [Indexed: 06/05/2024] Open
Abstract
I am often asked by students and younger colleagues and now by the editors of this issue to tell the history of the development of the in vitro motility assay and the dual-beam single-molecule laser trap assay for myosin-driven actin filament movement, used widely as key assays for understanding how both muscle and nonmuscle myosin molecular motors work. As for all discoveries, the history of the development of the myosin assays involves many people who are not authors of the final publications, but without whom the assays would not have been developed as they are. Also, early experiences shape how one develops ideas and experiments, and influence future discoveries in major ways. I am pleased here to trace my own path and acknowledge the many individuals involved and my early science experiences that led to the work I and my students, postdoctoral fellows, and sabbatical visitors did to develop these assays. Mentors are too often overlooked in historical descriptions of discoveries, and my story starts with those who mentored me.
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Affiliation(s)
- James A. Spudich
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, United States
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Masri A, Lester SJ, Stendahl JC, Hegde SM, Sehnert AJ, Balaratnam G, Shah A, Fox S, Wang A. Long-Term Safety and Efficacy of Mavacamten in Symptomatic Obstructive Hypertrophic Cardiomyopathy: Interim Results of the PIONEER-OLE Study. J Am Heart Assoc 2024; 13:e030607. [PMID: 38591260 DOI: 10.1161/jaha.123.030607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 01/16/2024] [Indexed: 04/10/2024]
Abstract
BACKGROUND The phase 2 PIONEER-HCM (Phase 2 Open-label Pilot Study Evaluating Mavacamten in Subjects With Symptomatic Hypertrophic Cardiomyopathy and Left Ventricular Outflow Tract Obstruction) study showed that mavacamten improved left ventricular outflow tract gradients, exercise capacity, and symptoms in patients with obstructive hypertrophic cardiomyopathy (HCM), but the results of longer-term treatment are less well described. We report interim results from the PIONEER-OLE (PIONEER Open-Label Extension) study, the longest-term study of mavacamten in patients with symptomatic obstructive HCM. METHODS AND RESULTS Patients who previously completed PIONEER-HCM (n=20) were eligible to enroll in PIONEER-OLE. Patients received oral mavacamten, 5 mg once daily (starting dose), with individualized dose titration at week 6. Evaluations included serial monitoring of safety, echocardiography, Kansas City Cardiomyopathy Questionnaire-Overall Summary Score, and serum NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels. Thirteen patients enrolled and received mavacamten (median study duration at data cutoff, 201 weeks). Most patients (92.3%) received β-blockers concomitantly. Treatment-emergent adverse events were predominantly mild/moderate. One patient had an isolated reduction in left ventricular ejection fraction to 47%, which recovered and remained normal with continued treatment at a reduced dose. At week 180, mavacamten was associated with New York Heart Association class improvements from baseline (class II to I, n=9; class III to II, n=1; and unchanged, n=2), sustained reductions in left ventricular outflow tract gradients (mean [SD] change from baseline: resting, -50 [55] mm Hg; Valsalva, -70 [41] mm Hg), and serum NT-proBNP levels (median [interquartile range] change from baseline: -498 [-2184 to -76] ng/L), and improved Kansas City Cardiomyopathy Questionnaire-Overall Summary Score (mean [SD] change from baseline: +17 [16]). CONCLUSIONS This long-term analysis supports the continued safety and effectiveness of mavacamten for >3 years in obstructive HCM. REGISTRATION URL: https://www.clinicaltrials.gov; Unique identifier: NCT03496168.
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Affiliation(s)
- Ahmad Masri
- Division of Cardiology, Hypertrophic Cardiomyopathy Center, School of Medicine Oregon Health & Science University Portland OR
| | - Steven J Lester
- Department of Cardiovascular Diseases Mayo Clinic Arizona Phoenix AZ
| | - John C Stendahl
- Section of Cardiovascular Medicine, Department of Internal Medicine Yale School of Medicine New Haven CT
| | - Sheila M Hegde
- Division of Cardiovascular Medicine Brigham and Women's Hospital Boston MA
| | | | | | | | | | - Andrew Wang
- Duke Cardiology Duke University Hospital Durham NC
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Abstract
Force generation in striated muscle is primarily controlled by structural changes in the actin-containing thin filaments triggered by an increase in intracellular calcium concentration. However, recent studies have elucidated a new class of regulatory mechanisms, based on the myosin-containing thick filament, that control the strength and speed of contraction by modulating the availability of myosin motors for the interaction with actin. This review summarizes the mechanisms of thin and thick filament activation that regulate the contractility of skeletal and cardiac muscle. A novel dual-filament paradigm of muscle regulation is emerging, in which the dynamics of force generation depends on the coordinated activation of thin and thick filaments. We highlight the interfilament signaling pathways based on titin and myosin-binding protein-C that couple thin and thick filament regulatory mechanisms. This dual-filament regulation mediates the length-dependent activation of cardiac muscle that underlies the control of the cardiac output in each heartbeat.
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Affiliation(s)
- Elisabetta Brunello
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences and British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom; ,
| | - Luca Fusi
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences and British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom; ,
- Centre for Human and Applied Physiological Sciences, School of Basic and Medical Biosciences, King's College London, London, United Kingdom
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Wong FL, Bunch TA, Lepak VC, Steedman AL, Colson BA. Cardiac myosin-binding protein C N-terminal interactions with myosin and actin filaments: Opposite effects of phosphorylation and M-domain mutations. J Mol Cell Cardiol 2024; 186:125-137. [PMID: 38008210 PMCID: PMC10872421 DOI: 10.1016/j.yjmcc.2023.11.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 10/26/2023] [Accepted: 11/17/2023] [Indexed: 11/28/2023]
Abstract
N-terminal cardiac myosin-binding protein C (cMyBP-C) domains (C0-C2) bind to thick (myosin) and thin (actin) filaments to coordinate contraction and relaxation of the heart. These interactions are regulated by phosphorylation of the M-domain situated between domains C1 and C2. In cardiomyopathies and heart failure, phosphorylation of cMyBP-C is significantly altered. We aimed to investigate how cMyBP-C interacts with myosin and actin. We developed complementary, high-throughput, C0-C2 FRET-based binding assays for myosin and actin to characterize the effects due to 5 HCM-linked variants or functional mutations in unphosphorylated and phosphorylated C0-C2. The assays indicated that phosphorylation decreases binding to both myosin and actin, whereas the HCM mutations in M-domain generally increase binding. The effects of mutations were greatest in phosphorylated C0-C2, and some mutations had a larger effect on actin than myosin binding. Phosphorylation also altered the spatial relationship of the probes on C0-C2 and actin. The magnitude of these structural changes was dependent on C0-C2 probe location (C0, C1, or M-domain). We conclude that binding can differ between myosin and actin due to phosphorylation or mutations. Additionally, these variables can change the mode of binding, affecting which of the interactions in cMyBP-C N-terminal domains with myosin or actin take place. The opposite effects of phosphorylation and M-domain mutations is consistent with the idea that cMyBP-C phosphorylation is critical for normal cardiac function. The precision of these assays is indicative of their usefulness in high-throughput screening of drug libraries for targeting cMyBP-C as therapy.
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Affiliation(s)
- Fiona L Wong
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85724, United States
| | - Thomas A Bunch
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85724, United States
| | - Victoria C Lepak
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85724, United States
| | - Allison L Steedman
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85724, United States
| | - Brett A Colson
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85724, United States.
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7
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Coats CJ, Maron MS, Abraham TP, Olivotto I, Lee MMY, Arad M, Cardim N, Ma CS, Choudhury L, Düngen HD, Garcia-Pavia P, Hagège AA, Lewis GD, Michels M, Oreziak A, Owens AT, Tfelt-Hansen J, Veselka J, Watkins HC, Heitner SB, Jacoby DL, Kupfer S, Malik FI, Meng L, Wohltman A, Masri A. Exercise Capacity in Patients With Obstructive Hypertrophic Cardiomyopathy: SEQUOIA-HCM Baseline Characteristics and Study Design. JACC. HEART FAILURE 2024; 12:199-215. [PMID: 38032573 DOI: 10.1016/j.jchf.2023.10.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 10/03/2023] [Accepted: 10/11/2023] [Indexed: 12/01/2023]
Abstract
Patients with obstructive hypertrophic cardiomyopathy (oHCM) have increased risk of arrhythmia, stroke, heart failure, and sudden death. Contemporary management of oHCM has decreased annual hospitalization and mortality rates, yet patients have worsening health-related quality of life due to impaired exercise capacity and persistent residual symptoms. Here we consider the design of clinical trials evaluating potential oHCM therapies in the context of SEQUOIA-HCM (Safety, Efficacy, and Quantitative Understanding of Obstruction Impact of Aficamten in HCM). This large, phase 3 trial is now fully enrolled (N = 282). Baseline characteristics reflect an ethnically diverse population with characteristics typical of patients encountered clinically with substantial functional and symptom burden. The study will assess the effect of aficamten vs placebo, in addition to standard-of-care medications, on functional capacity and symptoms over 24 weeks. Future clinical trials could model the approach in SEQUOIA-HCM to evaluate the effect of potential therapies on the burden of oHCM. (Safety, Efficacy, and Quantitative Understanding of Obstruction Impact of Aficamten in HCM [SEQUOIA-HCM]; NCT05186818).
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Affiliation(s)
- Caroline J Coats
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, United Kingdom.
| | - Martin S Maron
- Hypertrophic Cardiomyopathy Center at Lahey Medical Center, Burlington, Massachusetts, USA
| | | | - Iacopo Olivotto
- Meyer Children's Hospital, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Florence, Italy
| | - Matthew M Y Lee
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, United Kingdom
| | - Michael Arad
- Leviev Heart Center, Sheba Medical Center, Israel; Tel Aviv University, Medical School, Israel
| | | | - Chang-Sheng Ma
- Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Lubna Choudhury
- Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | | | - Pablo Garcia-Pavia
- Hospital Universitario Puerta de Hierro de Majadahonda, IDIPHISA, CIBERCV, and Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Albert A Hagège
- Département de Cardiologie, Assistance Publique Hôpitaux de Paris, Hôpital Européen Georges-Pompidou, Paris, France
| | | | | | | | - Anjali T Owens
- University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jacob Tfelt-Hansen
- Section of Forensic Genetics, Department of Forensic Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Cardiology, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Josef Veselka
- University Hospital Motol and 2nd Medical School, Charles University, Prague, Czech Republic
| | - Hugh C Watkins
- Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | | | - Daniel L Jacoby
- Cytokinetics Incorporated, South San Francisco, California, USA
| | - Stuart Kupfer
- Cytokinetics Incorporated, South San Francisco, California, USA
| | - Fady I Malik
- Cytokinetics Incorporated, South San Francisco, California, USA
| | - Lisa Meng
- Cytokinetics Incorporated, South San Francisco, California, USA
| | - Amy Wohltman
- Cytokinetics Incorporated, South San Francisco, California, USA
| | - Ahmad Masri
- Oregon Health and Science University, Portland, Oregon, USA
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Bodt SML, Ge J, Ma W, Rasicci DV, Desetty R, McCammon JA, Yengo CM. Dilated cardiomyopathy mutation in beta-cardiac myosin enhances actin activation of the power stroke and phosphate release. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.10.566646. [PMID: 38014187 PMCID: PMC10680644 DOI: 10.1101/2023.11.10.566646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Inherited mutations in human beta-cardiac myosin (M2β) can lead to severe forms of heart failure. The E525K mutation in M2β is associated with dilated cardiomyopathy (DCM) and was found to stabilize the interacting heads motif (IHM) and autoinhibited super-relaxed (SRX) state in dimeric heavy meromyosin. However, in monomeric M2β subfragment 1 (S1) we found that E525K enhances (3-fold) the maximum steady-state actin-activated ATPase activity ( k cat ) and decreases (6-fold) the actin concentration at which ATPase is one-half maximal ( K ATPase ). We also found a 3 to 4-fold increase in the actin-activated power stroke and phosphate release rate constants at 30 μM actin, which overall enhanced the duty ratio 3-fold. Loaded motility assays revealed that the enhanced intrinsic motor activity translates to increased ensemble force in M2β S1. Glutamate 525, located near the actin binding region in the so-called activation loop, is highly conserved and predicted to form a salt-bridge with another conserved residue (lysine 484) in the relay helix. Enhanced sampling molecular dynamics simulations predict that the charge reversal mutation disrupts the E525-K484 salt-bridge, inducing conformations with a more flexible relay helix and a wide phosphate release tunnel. Our results highlight a highly conserved allosteric pathway associated with actin activation of the power stroke and phosphate release and suggest an important feature of the autoinhibited IHM is to prevent this region of myosin from interacting with actin. The ability of the E525K mutation to stabilize the IHM likely overrides the enhanced intrinsic motor properties, which may be key to triggering DCM pathogenesis. Significance Statement Heart disease can be caused by inherited mutations in beta-cardiac myosin, the molecular motor that powers systolic contraction in the ventricles of the heart. However, it remains unclear how these mutations lead to contractile dysfunction and pathogenic remodeling of the heart. We investigated a unique dilated cardiomyopathy mutation (E525K) that dramatically stabilizes the autoinhibited state while enhancing intrinsic motor function. Thus, we examined how this mutation impacts transient kinetic steps of the ATPase cycle, motile properties, and structural changes associated with the power stroke and phosphate release. Our results provide a kinetic and structural basis for how beta-cardiac myosin mutations may disrupt molecular-level contractile function in complex ways, which may inform the development of targeted therapeutics.
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Abbasi Yeganeh F, Rastegarpouyani H, Li J, Taylor KA. Structure of the Drosophila melanogaster Flight Muscle Myosin Filament at 4.7 Å Resolution Reveals New Details of Non-Myosin Proteins. Int J Mol Sci 2023; 24:14936. [PMID: 37834384 PMCID: PMC10573858 DOI: 10.3390/ijms241914936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 09/29/2023] [Accepted: 10/01/2023] [Indexed: 10/15/2023] Open
Abstract
Striated muscle thick filaments are composed of myosin II and several non-myosin proteins which define the filament length and modify its function. Myosin II has a globular N-terminal motor domain comprising its catalytic and actin-binding activities and a long α-helical, coiled tail that forms the dense filament backbone. Myosin alone polymerizes into filaments of irregular length, but striated muscle thick filaments have defined lengths that, with thin filaments, define the sarcomere structure. The motor domain structure and function are well understood, but the myosin filament backbone is not. Here we report on the structure of the flight muscle thick filaments from Drosophila melanogaster at 4.7 Å resolution, which eliminates previous ambiguities in non-myosin densities. The full proximal S2 region is resolved, as are the connecting densities between the Ig domains of stretchin-klp. The proteins, flightin, and myofilin are resolved in sufficient detail to build an atomic model based on an AlphaFold prediction. Our results suggest a method by which flightin and myofilin cooperate to define the structure of the thick filament and explains a key myosin mutation that affects flightin incorporation. Drosophila is a genetic model organism for which our results can define strategies for functional testing.
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Affiliation(s)
- Fatemeh Abbasi Yeganeh
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4380, USA; (F.A.Y.); (H.R.); (J.L.)
| | - Hosna Rastegarpouyani
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4380, USA; (F.A.Y.); (H.R.); (J.L.)
- Department of Biological Science, Florida State University, Tallahassee, FL 32306-4380, USA
| | - Jiawei Li
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4380, USA; (F.A.Y.); (H.R.); (J.L.)
| | - Kenneth A. Taylor
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4380, USA; (F.A.Y.); (H.R.); (J.L.)
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10
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Quedan D, Singh R, Akel A, Bernardino AL, Thang C, Bhaskaruni M, Haldankar A, Tanner BCW, Root DD. Cooperative & competitive binding of anti-myosin tail antibodies revealed by super-resolution microscopy. Arch Biochem Biophys 2023; 747:109753. [PMID: 37714251 DOI: 10.1016/j.abb.2023.109753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 09/08/2023] [Accepted: 09/11/2023] [Indexed: 09/17/2023]
Abstract
The MF30 monoclonal antibody, which binds to the myosin subfragment-2 (S2), was found to increase the extent of myofibril shortening. Yet, previous observations found no effect of this antibody on actin sliding over myosin during in vitro motility assays with purified proteins in which myosin binding protein C (MyBPC) was absent. MF30 is hypothesized to enhance the availability of myosin heads (subfragment-1 or S1) to bind actin by destabilizing the myosin S2 coiled-coil and sterically blocking S2 from binding S1. The mechanism of action likely includes MF30's substantial size, thereby inhibiting S1 heads and MyBPC from binding S2. Hypothetically, MF30 should enhance the ON state of myosin, thereby increasing muscle contraction. Our findings indicate that MF30 binds preferentially to the unfolded heavy chains of S2, displaying positive cooperativity. However, the dose-response curve of MF30's enhancement of myofibril shortening did not suggest complex interactions with S2. Single, double, and triple-stained myofibrils with increasing amounts of antibodies against myosin rods indicate a possible competition with MyBPC. Additional assays revealed decreased fluorescence intensity at the C-zone (central zone in the sarcomere, where MyBPC is located), where MyBPC may inhibit MF30 binding. Another monoclonal antibody named MF20, which binds to the light meromyosin (LMM) without affecting myofibril contraction, showed less reduction in fluorescence intensity at the C-zone in expansion microscopy than MF30. Expansion microscopy images of myofibrils labeled with MF20 revealed labeling of the A-band (anisotropic band) and a slight reduction in the labeling at the C-zone. The staining pattern obtained from the expansion microscopy image was consistent with images from photolocalization microscopy which required the synthesis of unique photoactivatable quantum dots, and Zeiss Airyscan imaging as well as alternative expansion microscopy digestion methods. Consistent with the hypothesis that MF30 competes with MyBPC binding to S2, cardiac tissue from MyBPC knockout mice was stained more intensely, especially in the C-zone, by MF30 compared to the wild type.
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Affiliation(s)
- Dua'a Quedan
- Department of Biological Sciences, Division of Biochemistry and Molecular Biology, University of North Texas, Denton, TX, 76203, USA
| | - Rohit Singh
- Department of Biological Sciences, Division of Biochemistry and Molecular Biology, University of North Texas, Denton, TX, 76203, USA
| | - Amal Akel
- Department of Biological Sciences, Division of Biochemistry and Molecular Biology, University of North Texas, Denton, TX, 76203, USA
| | - Andrea L Bernardino
- Department of Biological Sciences, Division of Biochemistry and Molecular Biology, University of North Texas, Denton, TX, 76203, USA
| | - Christopher Thang
- Department of Biological Sciences, Division of Biochemistry and Molecular Biology, University of North Texas, Denton, TX, 76203, USA
| | - Mithilesh Bhaskaruni
- Department of Biological Sciences, Division of Biochemistry and Molecular Biology, University of North Texas, Denton, TX, 76203, USA
| | - Anushka Haldankar
- Department of Biological Sciences, Division of Biochemistry and Molecular Biology, University of North Texas, Denton, TX, 76203, USA
| | - Bertrand C W Tanner
- Department of Integrative Physiology & Neuroscience, Washington State University, Pullman, WA, 99164, USA
| | - Douglas D Root
- Department of Biological Sciences, Division of Biochemistry and Molecular Biology, University of North Texas, Denton, TX, 76203, USA.
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Sonne A, Antonovic AK, Melhedegaard E, Akter F, Andersen JL, Jungbluth H, Witting N, Vissing J, Zanoteli E, Fornili A, Ochala J. Abnormal myosin post-translational modifications and ATP turnover time associated with human congenital myopathy-related RYR1 mutations. Acta Physiol (Oxf) 2023; 239:e14035. [PMID: 37602753 PMCID: PMC10909445 DOI: 10.1111/apha.14035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 08/07/2023] [Accepted: 08/08/2023] [Indexed: 08/22/2023]
Abstract
AIM Conditions related to mutations in the gene encoding the skeletal muscle ryanodine receptor 1 (RYR1) are genetic muscle disorders and include congenital myopathies with permanent weakness, as well as episodic phenotypes such as rhabdomyolysis/myalgia. Although RYR1 dysfunction is the primary mechanism in RYR1-related disorders, other downstream pathogenic events are less well understood and may include a secondary remodeling of major contractile proteins. Hence, in the present study, we aimed to investigate whether congenital myopathy-related RYR1 mutations alter the regulation of the most abundant contractile protein, myosin. METHODS We used skeletal muscle tissues from five patients with RYR1-related congenital myopathy and compared those with five controls and five patients with RYR1-related rhabdomyolysis/myalgia. We then defined post-translational modifications on myosin heavy chains (MyHCs) using LC/MS. In parallel, we determined myosin relaxed states using Mant-ATP chase experiments and performed molecular dynamics (MD) simulations. RESULTS LC/MS revealed two additional phosphorylations (Thr1309-P and Ser1362-P) and one acetylation (Lys1410-Ac) on the β/slow MyHC of patients with congenital myopathy. This method also identified six acetylations that were lacking on MyHC type IIa of these patients (Lys35-Ac, Lys663-Ac, Lys763-Ac, Lys1171-Ac, Lys1360-Ac, and Lys1733-Ac). MD simulations suggest that modifying myosin Ser1362 impacts the protein structure and dynamics. Finally, Mant-ATP chase experiments showed a faster ATP turnover time of myosin heads in the disordered-relaxed conformation. CONCLUSIONS Altogether, our results suggest that RYR1 mutations have secondary negative consequences on myosin structure and function, likely contributing to the congenital myopathic phenotype.
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Affiliation(s)
- Alexander Sonne
- Department of Biomedical Sciences, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Anna Katarina Antonovic
- Department of Chemistry, School of Physical and Chemical SciencesQueen Mary University of LondonLondonUK
| | - Elise Melhedegaard
- Department of Biomedical Sciences, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Fariha Akter
- Department of Chemistry, School of Physical and Chemical SciencesQueen Mary University of LondonLondonUK
| | - Jesper L. Andersen
- Department of Orthopaedic Surgery, Institute of Sports Medicine CopenhagenCopenhagen University Hospital, Bispebjerg and FrederiksbergCopenhagenDenmark
- Center for Healthy Aging, Department of Clinical MedicineUniversity of CopenhagenCopenhagenDenmark
| | - Heinz Jungbluth
- Department of Paediatric NeurologyEvelina London Children's HospitalLondonUK
- Randall Centre for Cell and Molecular Biophysics, Muscle Signalling Section, Faculty of Life Sciences and MedicineKing's College LondonLondonUK
| | - Nanna Witting
- Copenhagen Neuromuscular Center, Department of NeurologyUniversity of CopenhagenCopenhagenDenmark
| | - John Vissing
- Copenhagen Neuromuscular Center, Department of NeurologyUniversity of CopenhagenCopenhagenDenmark
| | - Edmar Zanoteli
- Departamento de Neurologia, Faculdade de Medicina, Hospital das ClínicasUniversidade de São PauloSão PauloBrazil
| | - Arianna Fornili
- Department of Chemistry, School of Physical and Chemical SciencesQueen Mary University of LondonLondonUK
| | - Julien Ochala
- Department of Biomedical Sciences, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
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12
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Zhu M, Reyes KRL, Bilgili G, Siegel RJ, Lee Claggett B, Wong TC, Masri A, Naidu SS, Willeford A, Rader F. Medical Therapies to Improve Left Ventricular Outflow Obstruction and Diastolic Function in Hypertrophic Cardiomyopathy. JACC. ADVANCES 2023; 2:100622. [PMID: 38938334 PMCID: PMC11198509 DOI: 10.1016/j.jacadv.2023.100622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 08/10/2023] [Indexed: 06/29/2024]
Abstract
Hypertrophic cardiomyopathy-both obstructive hypertrophic cardiomyopathy (oHCM) and nonobstructive hypertrophic cardiomyopathy (nHCM) subtypes-is the most common monogenic cardiomyopathy. Its structural hallmarks are abnormal thickening of the myocardium and hyperdynamic contractility, while its hemodynamic consequences are left ventricular outflow tract or intracavitary obstruction (in oHCM) and diastolic dysfunction (in both oHCM and nHCM). Several medical therapies are routinely used to improve these abnormalities with the goal to decrease symptom burden in patients with HCM. Current guidelines recommend nonvasodilating beta blockers as first-line and nondihydropyridine calcium channel blockers followed by disopyramide as second- and third-line medical therapies for symptomatic oHCM and give weaker recommendations for beta blockers and calcium channel blockers in nHCM. These recommendations are based on small studies-mostly nonrandomized-and expert opinion. Our review will summarize the available data on the effectiveness of commonly prescribed medications used in oHCM and nHCM to uncover knowledge gaps, but also new data on cardiac myosin inhibitors.
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Affiliation(s)
- Mason Zhu
- Georgetown University School of Medicine, Washington, DC, USA
| | | | - Gizem Bilgili
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Robert J. Siegel
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Brian Lee Claggett
- Cardiovascular Division, Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Timothy C. Wong
- Division of Cardiology, Department of Medicine, University of Pittsburgh Medical Center, Heart and Vascular Institute, Pittsburgh, Pennsylvania, USA
| | - Ahmad Masri
- Knight Cardiovascular Institute, Oregon Health Sciences University Medical Center, Portland, Oregon, USA
| | - Srihari S. Naidu
- Department of Cardiology, Westchester Medical Center, Valhalla, New York, USA
| | - Andrew Willeford
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California-San Diego Health, San Diego, California, USA
| | - Florian Rader
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
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13
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Tian Z, Li L, Li X, Wang J, Zhang Q, Li Z, Peng D, Yang P, Ma W, Wang F, Jin W, Cheng X, Sun J, Fu Y, Lyu C, Zhang S. Effect of Mavacamten on Chinese Patients With Symptomatic Obstructive Hypertrophic Cardiomyopathy: The EXPLORER-CN Randomized Clinical Trial. JAMA Cardiol 2023; 8:957-965. [PMID: 37639259 PMCID: PMC10463173 DOI: 10.1001/jamacardio.2023.3030] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 07/21/2023] [Indexed: 08/29/2023]
Abstract
Importance Mavacamten has shown clinical benefits in global studies for patients with obstructive hypertrophic cardiomyopathy (oHCM), but evidence in the Asian population is lacking. Objective To evaluate the safety and efficacy of mavacamten compared with placebo for Chinese patients with symptomatic oHCM. Design, Setting, and Participants This phase 3, randomized, double-blind, placebo-controlled clinical trial was conducted at 12 hospitals in China. Between January 4 and August 5, 2022, patients with oHCM and a left ventricular outflow tract (LVOT) gradient of 50 mm Hg or more and New York Heart Association (NYHA) class II or III symptoms were enrolled and received treatment for 30 weeks. Interventions Patients were randomized 2:1 to receive mavacamten (starting at 2.5 mg once daily) or placebo for 30 weeks. Main Outcomes and Measures The primary end point was change in Valsalva LVOT peak gradient from baseline to week 30. Left ventricular outflow tract gradients and left ventricular ejection fraction (LVEF) were assessed by echocardiography, while left ventricular mass index (LVMI) was determined by cardiac magnetic resonance imaging. Analysis was performed on an intention-to-treat basis. Results A total of 81 patients (mean [SD] age, 51.9 [11.9] years; 58 men [71.6%]) were randomized. Mavacamten demonstrated a significant improvement in the primary end point compared with placebo (least-squares mean [LSM] difference, -70.3 mm Hg; 95% CI, -89.6 to -50.9 mm Hg; 1-sided P < .001). Similar trends were demonstrated for resting LVOT peak gradient (LSM difference, -55.0 mm Hg; 95% CI, -69.1 to -40.9 mm Hg). At week 30, more patients receiving mavacamten than placebo achieved a Valsalva LVOT peak gradient less than 30 mm Hg (48.1% [26 of 54] vs 3.7% [1 of 27]), less than 50 mm Hg (59.3% [32 of 54] vs 7.4% [2 of 27]), and NYHA class improvement (59.3% [32 of 54] vs 14.8% [4 of 27]). Greater improvements were also observed with mavacamten regarding the Kansas City Cardiomyopathy Questionnaire Clinical Summary Score (LSM difference, 10.2; 95% CI, 4.4-16.1), N-terminal pro-B-type natriuretic peptide level (proportion of geometric mean ratio, 0.18; 95% CI, 0.13-0.24), high-sensitivity cardiac troponin I level (proportion of geometric mean ratio, 0.34; 95% CI, 0.27-0.42), and LVMI (mean difference, -30.8 g/m2; 95% CI, -41.6 to -20.1 g/m2). Safety and tolerability were similar between mavacamten and placebo. No patients experienced LVEF less than 50%. Conclusions Mavacamten significantly improved Valsalva LVOT gradient vs placebo for Chinese patients. All secondary efficacy end points were also improved. Mavacamten was well tolerated with no new safety signals. This study supports the efficacy and safety of mavacamten in diverse populations, including Chinese patients. Trial Registration ClinicalTrials.gov Identifier: NCT05174416.
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Affiliation(s)
- Zhuang Tian
- Department of Cardiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Liwen Li
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical Sciences, Southern Medical University, Guangzhou, Guangdong Province, China
| | - Xiaoyan Li
- Department of Cardiology, Renmin Hospital of Wuhan University, Hubei General Hospital, Wuhan, Hubei Province, China
| | - Jian’an Wang
- Department of Cardiology, the Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, China
| | - Qing Zhang
- Department of Cardiology, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China
| | - Zhanquan Li
- Department of Cardiology, the People’s Hospital of Liaoning Province, Shenyang, Liaoning Province, China
| | - Daoquan Peng
- Department of Cardiology, the Second Xiangya Hospital of Central South University, Changsha, Hunan Province, China
| | - Ping Yang
- Department of Cardiology, China-Japan Union Hospital of Jilin University, Changchun, Jilin Province, China
| | - Wei Ma
- Department of Cardiology, Peking University First Hospital, Beijing, China
| | - Fang Wang
- Department of Cardiology, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, China
| | - Wei Jin
- Department of Cardiology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Xiang Cheng
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China
| | - Jing Sun
- Shanghai LianBio Development Co, Ltd, Shanghai, China
| | - Yiqun Fu
- Shanghai LianBio Development Co, Ltd, Shanghai, China
| | - Cheng Lyu
- Shanghai LianBio Development Co, Ltd, Shanghai, China
| | - Shuyang Zhang
- Department of Cardiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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14
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Kaur S, Desai M. Unmet needs and future directions in hypertrophic cardiomyopathy. Prog Cardiovasc Dis 2023; 80:1-7. [PMID: 37562518 DOI: 10.1016/j.pcad.2023.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 08/07/2023] [Indexed: 08/12/2023]
Abstract
Hypertrophic cardiomyopathy (HCM) is a highly treatable monogenetic disorder affecting nearly 0.2% of the population. The high burden of this disease demands suitable measures for early diagnosis and preventing as well as tackling misdiagnosis. While conventionally available therapies have been efficacious in reducing symptoms, they have not been able to change the natural history of the disease. The landscape of medical treatment is rapidly changing with advent of novel pharmacotherapies such as cardiac myosin inhibitors. Ongoing investigations in gene editing have demonstrated benefits in correcting underlying genetic mutations and this is where the future of treatment lies. Contemporary procedural techniques as alternatives to available septal reduction therapies independent of coronary vascular anatomy are also emerging. This review details the recent developments, unmet needs and future directions in diagnosis, medical and invasive treatment of HCM.
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Affiliation(s)
- Simrat Kaur
- Department of Cardiology, Heart, Vascular and Thoracic Institution, Cleveland Clinic, USA
| | - Milind Desai
- Department of Cardiology, Heart, Vascular and Thoracic Institution, Cleveland Clinic, USA.
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15
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Månsson A, Ušaj M, Moretto L, Matusovsky O, Velayuthan LP, Friedman R, Rassier DE. New paradigms in actomyosin energy transduction: Critical evaluation of non-traditional models for orthophosphate release. Bioessays 2023; 45:e2300040. [PMID: 37366639 DOI: 10.1002/bies.202300040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 05/30/2023] [Accepted: 06/01/2023] [Indexed: 06/28/2023]
Abstract
Release of the ATP hydrolysis product ortophosphate (Pi) from the active site of myosin is central in chemo-mechanical energy transduction and closely associated with the main force-generating structural change, the power-stroke. Despite intense investigations, the relative timing between Pi-release and the power-stroke remains poorly understood. This hampers in depth understanding of force production by myosin in health and disease and our understanding of myosin-active drugs. Since the 1990s and up to today, models that incorporate the Pi-release either distinctly before or after the power-stroke, in unbranched kinetic schemes, have dominated the literature. However, in recent years, alternative models have emerged to explain apparently contradictory findings. Here, we first compare and critically analyze three influential alternative models proposed previously. These are either characterized by a branched kinetic scheme or by partial uncoupling of Pi-release and the power-stroke. Finally, we suggest critical tests of the models aiming for a unified picture.
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Affiliation(s)
- Alf Månsson
- Department of Chemistry and Biomedical Sciences, Linnaeus University, Kalmar, Sweden
| | - Marko Ušaj
- Department of Chemistry and Biomedical Sciences, Linnaeus University, Kalmar, Sweden
| | - Luisa Moretto
- Department of Chemistry and Biomedical Sciences, Linnaeus University, Kalmar, Sweden
| | - Oleg Matusovsky
- Department of Kinesiology and Physical Education, McGill University, Montreal, Québec, Canada
| | - Lok Priya Velayuthan
- Department of Chemistry and Biomedical Sciences, Linnaeus University, Kalmar, Sweden
| | - Ran Friedman
- Department of Chemistry and Biomedical Sciences, Linnaeus University, Kalmar, Sweden
| | - Dilson E Rassier
- Department of Kinesiology and Physical Education, McGill University, Montreal, Québec, Canada
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16
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Sebastian SA, Padda I, Lehr EJ, Johal G. Aficamten: A Breakthrough Therapy for Symptomatic Obstructive Hypertrophic Cardiomyopathy. Am J Cardiovasc Drugs 2023; 23:519-532. [PMID: 37526885 DOI: 10.1007/s40256-023-00599-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/19/2023] [Indexed: 08/02/2023]
Abstract
Aficamten is a novel cardiac myosin inhibitor that has demonstrated its ability to safely lower left ventricular outflow tract (LVOT) gradients and improve heart failure symptoms in patients with obstructive hypertrophic cardiomyopathy (HCM). Based on the REDWOOD-HCM open label extension (OLE) study, participants receiving aficamten had significantly reduced resting and Valsalva LVOT gradient within 2 weeks after initiating treatment, with ongoing improvements over 24 weeks, and recent evidence suggests effects can sustain up to 48 weeks. While beta-blockers, calcium channel blockers, and disopyramide have shown some benefits in managing HCM, they have limited direct impact on the underlying disease process in patients with obstructive HCM. Aficamten achieves its therapeutic effect by reducing hypercontractility and improving diastolic function in obstructive HCM. Mavacamten was the first cardiac myosin inhibitor approved for symptomatic obstructive HCM. However, aficamten has a shorter human half-life (t1/2) and fewer drug-drug interactions, making it a preferable treatment option. This review evaluates the long-term clinical value and safety of aficamten in patients with obstructive HCM based on available data from completed and ongoing clinical trials. Additionally, the molecular basis of sarcomere-targeted therapy in reducing LVOT gradients is explored, and its potential in managing obstructive HCM is discussed.
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Affiliation(s)
- Sneha Annie Sebastian
- Department of Internal Medicine, Azeezia Medical College, Kollam, Kerala, India.
- , Airdrie, Canada.
| | - Inderbir Padda
- Department of Internal Medicine, Richmond University Medical Center/Mount Sinai, Staten Island, NY, USA
| | - Eric J Lehr
- Division of Cardiac Surgery, Swedish Heart and Vascular Institute, Seattle, WA, USA
| | - Gurpreet Johal
- Department of Cardiology, University of Washington, Valley Medical Center, Seattle, WA, USA
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17
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Nag S, Gollapudi SK, Del Rio CL, Spudich JA, McDowell R. Mavacamten, a precision medicine for hypertrophic cardiomyopathy: From a motor protein to patients. SCIENCE ADVANCES 2023; 9:eabo7622. [PMID: 37506209 DOI: 10.1126/sciadv.abo7622] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 06/23/2023] [Indexed: 07/30/2023]
Abstract
Hypertrophic cardiomyopathy (HCM) is a primary myocardial disorder characterized by left ventricular hypertrophy, hyperdynamic contraction, and impaired relaxation of the heart. These functional derangements arise directly from altered sarcomeric function due to either mutations in genes encoding sarcomere proteins, or other defects such as abnormal energetics. Current treatment options do not directly address this causal biology but focus on surgical and extra-sarcomeric (sarcolemmal) pharmacological symptomatic relief. Mavacamten (formerly known as MYK-461), is a small molecule designed to regulate cardiac function at the sarcomere level by selectively but reversibly inhibiting the enzymatic activity of myosin, the fundamental motor of the sarcomere. This review summarizes the mechanism and translational progress of mavacamten from proteins to patients, describing how the mechanism of action and pharmacological characteristics, involving both systolic and diastolic effects, can directly target pathophysiological derangements within the cardiac sarcomere to improve cardiac structure and function in HCM. Mavacamten was approved by the Food and Drug Administration in April 2022 for the treatment of obstructive HCM and now goes by the commercial name of Camzyos. Full information about the risks, limitations, and side effects can be found at www.accessdata.fda.gov/drugsatfda_docs/label/2022/214998s000lbl.pdf.
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Affiliation(s)
- Suman Nag
- MyoKardia Inc., a wholly owned subsidiary of Bristol Myers Squibb, Brisbane, CA 94005, USA
| | - Sampath K Gollapudi
- MyoKardia Inc., a wholly owned subsidiary of Bristol Myers Squibb, Brisbane, CA 94005, USA
| | - Carlos L Del Rio
- MyoKardia Inc., a wholly owned subsidiary of Bristol Myers Squibb, Brisbane, CA 94005, USA
- Cardiac Consulting, 1630 S Delaware St. #56426, San Mateo, CA 94403, USA
| | | | - Robert McDowell
- MyoKardia Inc., a wholly owned subsidiary of Bristol Myers Squibb, Brisbane, CA 94005, USA
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18
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Lewis CT, Tabrizian L, Nielsen J, Laitila J, Beck TN, Olsen MS, Ognjanovic MM, Aagaard P, Hokken R, Laugesen S, Ingersen A, Andersen JL, Soendenbroe C, Helge JW, Dela F, Larsen S, Sahl RE, Rømer T, Hansen MT, Frandsen J, Suetta C, Ochala J. Physical activity impacts resting skeletal muscle myosin conformation and lowers its ATP consumption. J Gen Physiol 2023; 155:e202213268. [PMID: 37227464 PMCID: PMC10225618 DOI: 10.1085/jgp.202213268] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 04/07/2023] [Accepted: 05/15/2023] [Indexed: 05/26/2023] Open
Abstract
It has recently been established that myosin, the molecular motor protein, is able to exist in two conformations in relaxed skeletal muscle. These conformations are known as the super-relaxed (SRX) and disordered-relaxed (DRX) states and are finely balanced to optimize ATP consumption and skeletal muscle metabolism. Indeed, SRX myosins are thought to have a 5- to 10-fold reduction in ATP turnover compared with DRX myosins. Here, we investigated whether chronic physical activity in humans would be associated with changes in the proportions of SRX and DRX skeletal myosins. For that, we isolated muscle fibers from young men of various physical activity levels (sedentary, moderately physically active, endurance-trained, and strength-trained athletes) and ran a loaded Mant-ATP chase protocol. We observed that in moderately physically active individuals, the amount of myosin molecules in the SRX state in type II muscle fibers was significantly greater than in age-matched sedentary individuals. In parallel, we did not find any difference in the proportions of SRX and DRX myosins in myofibers between highly endurance- and strength-trained athletes. We did however observe changes in their ATP turnover time. Altogether, these results indicate that physical activity level and training type can influence the resting skeletal muscle myosin dynamics. Our findings also emphasize that environmental stimuli such as exercise have the potential to rewire the molecular metabolism of human skeletal muscle through myosin.
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Affiliation(s)
- Christopher T.A. Lewis
- Department of Biomedical Sciences, Xlab, Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lee Tabrizian
- Department of Biomedical Sciences, Xlab, Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Joachim Nielsen
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Jenni Laitila
- Department of Biomedical Sciences, Xlab, Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas N. Beck
- Department of Biomedical Sciences, Xlab, Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mathilde S. Olsen
- Department of Biomedical Sciences, Xlab, Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Marija M. Ognjanovic
- Department of Biomedical Sciences, Xlab, Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Per Aagaard
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Rune Hokken
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Simon Laugesen
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Arthur Ingersen
- Department of Biomedical Sciences, Xlab, Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jesper L. Andersen
- Department of Orthopedic Surgery, Institute of Sports Medicine Copenhagen, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Casper Soendenbroe
- Department of Orthopedic Surgery, Institute of Sports Medicine Copenhagen, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jørn W. Helge
- Department of Biomedical Sciences, Xlab, Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Flemming Dela
- Department of Biomedical Sciences, Xlab, Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Geriatric and Palliative Medicine, Copenhagen University Hospital, Bispebjerg and Frederiksberg Hospital, Copenhagen, Denmark
| | - Steen Larsen
- Department of Biomedical Sciences, Xlab, Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Clinical Research Centre, Medical University of Bialystok, Bialystok, Poland
| | - Ronni E. Sahl
- Department of Biomedical Sciences, Xlab, Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tue Rømer
- Department of Biomedical Sciences, Xlab, Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mikkel T. Hansen
- Department of Biomedical Sciences, Xlab, Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jacob Frandsen
- Department of Biomedical Sciences, Xlab, Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Charlotte Suetta
- Department of Geriatric and Palliative Medicine, Copenhagen University Hospital, Bispebjerg and Frederiksberg Hospital, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Julien Ochala
- Department of Biomedical Sciences, Xlab, Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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19
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Grinzato A, Auguin D, Kikuti C, Nandwani N, Moussaoui D, Pathak D, Kandiah E, Ruppel KM, Spudich JA, Houdusse A, Robert-Paganin J. Cryo-EM structure of the folded-back state of human β-cardiac myosin. Nat Commun 2023; 14:3166. [PMID: 37258552 PMCID: PMC10232470 DOI: 10.1038/s41467-023-38698-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 05/11/2023] [Indexed: 06/02/2023] Open
Abstract
To save energy and precisely regulate cardiac contractility, cardiac muscle myosin heads are sequestered in an 'off' state that can be converted to an 'on' state when exertion is increased. The 'off' state is equated with a folded-back structure known as the interacting-heads motif (IHM), which is a regulatory feature of all class-2 muscle and non-muscle myosins. We report here the human β-cardiac myosin IHM structure determined by cryo-electron microscopy to 3.6 Å resolution, providing details of all the interfaces stabilizing the 'off' state. The structure shows that these interfaces are hot spots of hypertrophic cardiomyopathy mutations that are thought to cause hypercontractility by destabilizing the 'off' state. Importantly, the cardiac and smooth muscle myosin IHM structures dramatically differ, providing structural evidence for the divergent physiological regulation of these muscle types. The cardiac IHM structure will facilitate development of clinically useful new molecules that modulate IHM stability.
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Affiliation(s)
- Alessandro Grinzato
- CM01 beamline. European Synchrotron Radiation Facility (ESRF), Grenoble, France
| | - Daniel Auguin
- Structural Motility, Institut Curie, Paris Université Sciences et Lettres, Sorbonne Université, CNRS UMR144, F-75005, Paris, France
- Laboratoire de Biologie des Ligneux et des Grandes Cultures, Université d'Orléans, UPRES EA 1207, INRA-USC1328, F-45067, Orléans, France
| | - Carlos Kikuti
- Structural Motility, Institut Curie, Paris Université Sciences et Lettres, Sorbonne Université, CNRS UMR144, F-75005, Paris, France
| | - Neha Nandwani
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Dihia Moussaoui
- BM29 BIOSAXS beamline, European Synchrotron Radiation Facility (ESRF), Grenoble, France
| | - Divya Pathak
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Eaazhisai Kandiah
- CM01 beamline. European Synchrotron Radiation Facility (ESRF), Grenoble, France
| | - Kathleen M Ruppel
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA.
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, 94305, USA.
| | - James A Spudich
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Anne Houdusse
- Structural Motility, Institut Curie, Paris Université Sciences et Lettres, Sorbonne Université, CNRS UMR144, F-75005, Paris, France.
| | - Julien Robert-Paganin
- Structural Motility, Institut Curie, Paris Université Sciences et Lettres, Sorbonne Université, CNRS UMR144, F-75005, Paris, France.
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20
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Tamargo J, Agewall S, Borghi C, Ceconi C, Cerbai E, Dan GA, Ferdinandy P, Grove EL, Rocca B, Sulzgruber P, Semb AG, Sossalla S, Niessner A, Kaski JC, Dobrev D. New pharmacological agents and novel cardiovascular pharmacotherapy strategies in 2022. EUROPEAN HEART JOURNAL. CARDIOVASCULAR PHARMACOTHERAPY 2023; 9:pvad034. [PMID: 37169875 PMCID: PMC10236523 DOI: 10.1093/ehjcvp/pvad034] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 04/10/2023] [Accepted: 05/10/2023] [Indexed: 05/13/2023]
Abstract
Cardiovascular diseases (CVD) remain the leading cause of death worldwide and pharmacotherapy of most of them is suboptimal. Thus, there is a clear unmet clinical need to develop new pharmacological strategies with greater efficacy and better safety profiles. In this review, we summarize the most relevant advances in cardiovascular pharmacology in 2022 including the approval of first-in-class drugs that open new avenues for the treatment of obstructive hypertrophic cardiomyopathy (mavacamten), type 2 diabetes mellitus (tirzepatide), and heart failure (HF) independent of left ventricular ejection fraction (sodium-glucose cotransporter 2 inhibitors). We also dealt with fixed dose combination therapies repurposing different formulations of "old" drugs with well-known efficacy and safety for the treatment of patients with acute decompensated HF (acetazolamide plus loop diuretics), atherosclerotic cardiovascular disease (moderate-dose statin plus ezetimibe), Marfan syndrome (angiotensin receptor blockers plus β-blockers), and secondary cardiovascular prevention (i.e. low-dose aspirin, ramipril and atorvastatin), thereby filling existing gaps in knowledge, and opening new avenues for the treatment of CVD. Clinical trials confirming the role of dapagliflozin in patients with HF and mildly reduced or preserved ejection fraction, long-term evolocumab to reduce the risk of cardiovascular events, vitamin K antagonists for stroke prevention in patients with rheumatic heart disease-associated atrial fibrillation, antibiotic prophylaxis in patients at high risk for infective endocarditis before invasive dental procedures, and vutrisiran for the treatment of hereditary transthyretin-related amyloidosis with polyneuropathy were also reviewed. Finally, we briefly discuss recent clinical trials suggesting that FXIa inhibitors may have the potential to uncouple thrombosis from hemostasis and attenuate/prevent thromboembolic events with minimal disruption of hemostasis.
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Affiliation(s)
- Juan Tamargo
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense, Instituto de Investigación Sanitaria Gregorio Marañón, Plaza de Ramón y Cajal s/n, Madrid 28040, Spain
| | - Stefan Agewall
- Department of Cardiology, Oslo University Hospital and Institute of Clinical Medicine, Oslo University, Oslo, Norvay
| | - Claudio Borghi
- Department of Cardiovascular Medicine, University of Bologna-IRCCS AOU S. Orsola, Bologna, Italy
| | - Claudio Ceconi
- Unit of Cardiologia, ASST Garda, Desenzano del Garda, Italy
| | - Elisabetta Cerbai
- Department Neurofarba, Section of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Gheorghe A Dan
- “Carol Davila” University of Medicine, Colentina University Hospital, Bucharest, Romania
| | - Péter Ferdinandy
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
- Pharmahungary Group, Szeged, Hungary
| | - Erik Lerkevang Grove
- Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Faculty of Health, Aarhus University, Aarhus, Denmark
| | - Bianca Rocca
- Section of Pharmacology, Catholic University School of Medicine, Rome, Italy
| | - Patrick Sulzgruber
- Department of Medicine, Division of Cardiology, Medical University of Vienna, Vienna, Austria
| | - Anne Grete Semb
- Preventive Cario-Rheuma Clinic, Division of Research and Innovation, REMEDY Centre, Diakonhjemmet Hospital, Oslo, Norway
| | - Samuel Sossalla
- Department of Internal Medicine II, University Regensburg, Regensburg, Germany
| | - Alexander Niessner
- Department of Internal Medicine II, Division of Cardiology, Medical University of Vienna, Vienna, Austria
| | - Juan Carlos Kaski
- Molecular and Clinical Sciences Research Institute, St. George's, University of London, Cranmer Terrace, London SW17 0RE, UK
| | - Dobromir Dobrev
- Institute of Pharmacology, West-German Heart and Vascular Centre, University Duisburg-Essen, Essen, Germany
- Department of Medicine, Montreal Heart Institute and Université de Montréal, Montréal, Canada
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX, USA
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21
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De Lange WJ, Farrell ET, Hernandez JJ, Stempien A, Kreitzer CR, Jacobs DR, Petty DL, Moss RL, Crone WC, Ralphe JC. cMyBP-C ablation in human engineered cardiac tissue causes progressive Ca2+-handling abnormalities. J Gen Physiol 2023; 155:e202213204. [PMID: 36893011 PMCID: PMC10038829 DOI: 10.1085/jgp.202213204] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 01/02/2023] [Accepted: 02/14/2023] [Indexed: 03/10/2023] Open
Abstract
Truncation mutations in cardiac myosin binding protein C (cMyBP-C) are common causes of hypertrophic cardiomyopathy (HCM). Heterozygous carriers present with classical HCM, while homozygous carriers present with early onset HCM that rapidly progress to heart failure. We used CRISPR-Cas9 to introduce heterozygous (cMyBP-C+/-) and homozygous (cMyBP-C-/-) frame-shift mutations into MYBPC3 in human iPSCs. Cardiomyocytes derived from these isogenic lines were used to generate cardiac micropatterns and engineered cardiac tissue constructs (ECTs) that were characterized for contractile function, Ca2+-handling, and Ca2+-sensitivity. While heterozygous frame shifts did not alter cMyBP-C protein levels in 2-D cardiomyocytes, cMyBP-C+/- ECTs were haploinsufficient. cMyBP-C-/- cardiac micropatterns produced increased strain with normal Ca2+-handling. After 2 wk of culture in ECT, contractile function was similar between the three genotypes; however, Ca2+-release was slower in the setting of reduced or absent cMyBP-C. At 6 wk in ECT culture, the Ca2+-handling abnormalities became more pronounced in both cMyBP-C+/- and cMyBP-C-/- ECTs, and force production became severely depressed in cMyBP-C-/- ECTs. RNA-seq analysis revealed enrichment of differentially expressed hypertrophic, sarcomeric, Ca2+-handling, and metabolic genes in cMyBP-C+/- and cMyBP-C-/- ECTs. Our data suggest a progressive phenotype caused by cMyBP-C haploinsufficiency and ablation that initially is hypercontractile, but progresses to hypocontractility with impaired relaxation. The severity of the phenotype correlates with the amount of cMyBP-C present, with more severe earlier phenotypes observed in cMyBP-C-/- than cMyBP-C+/- ECTs. We propose that while the primary effect of cMyBP-C haploinsufficiency or ablation may relate to myosin crossbridge orientation, the observed contractile phenotype is Ca2+-mediated.
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Affiliation(s)
- Willem J. De Lange
- Departments of Pediatrics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Emily T. Farrell
- Departments of Pediatrics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Jonathan J. Hernandez
- Departments of Pediatrics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Alana Stempien
- Departments of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, USA
| | - Caroline R. Kreitzer
- Departments of Pediatrics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Derek R. Jacobs
- Departments of Pediatrics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Dominique L. Petty
- Departments of Pediatrics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Richard L. Moss
- Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Wendy C. Crone
- Departments of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, USA
- Engineering Physics, University of Wisconsin-Madison, Madison, WI, USA
- Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - J. Carter Ralphe
- Departments of Pediatrics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
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22
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Marcucci L. Muscle Mechanics and Thick Filament Activation: An Emerging Two-Way Interaction for the Vertebrate Striated Muscle Fine Regulation. Int J Mol Sci 2023; 24:ijms24076265. [PMID: 37047237 PMCID: PMC10094676 DOI: 10.3390/ijms24076265] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 03/12/2023] [Accepted: 03/21/2023] [Indexed: 03/29/2023] Open
Abstract
Contraction in striated muscle is classically described as regulated by calcium-mediated structural changes in the actin-containing thin filaments, which release the binding sites for the interaction with myosin motors to produce force. In this view, myosin motors, arranged in the thick filaments, are basically always ready to interact with the thin filaments, which ultimately regulate the contraction. However, a new “dual-filament” activation paradigm is emerging, where both filaments must be activated to generate force. Growing evidence from the literature shows that the thick filament activation has a role on the striated muscle fine regulation, and its impairment is associated with severe pathologies. This review is focused on the proposed mechanical feedback that activates the inactive motors depending on the level of tension generated by the active ones, the so-called mechanosensing mechanism. Since the main muscle function is to generate mechanical work, the implications on muscle mechanics will be highlighted, showing: (i) how non-mechanical modulation of the thick filament activation influences the contraction, (ii) how the contraction influences the activation of the thick filament and (iii) how muscle, through the mechanical modulation of the thick filament activation, can regulate its own mechanics. This description highlights the crucial role of the emerging bi-directional feedback on muscle mechanical performance.
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Affiliation(s)
- Lorenzo Marcucci
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy;
- Center for Biosystems Dynamics Research, RIKEN, Suita 565-0874, Japan
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23
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Song T, Landim-Vieira M, Ozdemir M, Gott C, Kanisicak O, Pinto JR, Sadayappan S. Etiology of genetic muscle disorders induced by mutations in fast and slow skeletal MyBP-C paralogs. Exp Mol Med 2023; 55:502-509. [PMID: 36854776 PMCID: PMC10073172 DOI: 10.1038/s12276-023-00953-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 12/14/2022] [Accepted: 12/15/2022] [Indexed: 03/02/2023] Open
Abstract
Skeletal muscle, a highly complex muscle type in the eukaryotic system, is characterized by different muscle subtypes and functions associated with specific myosin isoforms. As a result, skeletal muscle is the target of numerous diseases, including distal arthrogryposes (DAs). Clinically, DAs are a distinct disorder characterized by variation in the presence of contractures in two or more distal limb joints without neurological issues. DAs are inherited, and up to 40% of patients with this condition have mutations in genes that encode sarcomeric protein, including myosin heavy chains, troponins, and tropomyosin, as well as myosin binding protein-C (MYBPC). Our research group and others are actively studying the specific role of MYBPC in skeletal muscles. The MYBPC family of proteins plays a critical role in the contraction of striated muscles. More specifically, three paralogs of the MYBPC gene exist, and these are named after their predominant expression in slow-skeletal, fast-skeletal, and cardiac muscle as sMyBP-C, fMyBP-C, and cMyBP-C, respectively, and encoded by the MYBPC1, MYBPC2, and MYBPC3 genes, respectively. Although the physiology of various types of skeletal muscle diseases is well defined, the molecular mechanism underlying the pathological regulation of DAs remains to be elucidated. In this review article, we aim to highlight recent discoveries involving the role of skeletal muscle-specific sMyBP-C and fMyBP-C as well as their expression profile, localization in the sarcomere, and potential role(s) in regulating muscle contractility. Thus, this review provides an overall summary of MYBPC skeletal paralogs, their potential roles in skeletal muscle function, and future research directions.
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Affiliation(s)
- Taejeong Song
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, 45267, USA.
| | - Maicon Landim-Vieira
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL, 32306, USA
| | - Mustafa Ozdemir
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, 45267, USA
| | - Caroline Gott
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, 45267, USA
| | - Onur Kanisicak
- Department of Pathology and Laboratory Medicine, College of Medicine, University of Cincinnati, Cincinnati, OH, 45267, USA
| | - Jose Renato Pinto
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL, 32306, USA
| | - Sakthivel Sadayappan
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, 45267, USA.
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24
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Olivotto I, Udelson JE, Pieroni M, Rapezzi C. Genetic causes of heart failure with preserved ejection fraction: emerging pharmacological treatments. Eur Heart J 2023; 44:656-667. [PMID: 36582184 DOI: 10.1093/eurheartj/ehac764] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 11/13/2022] [Accepted: 11/26/2022] [Indexed: 12/31/2022] Open
Abstract
Heart failure with preserved ejection fraction (HFpEF) is a major driver of cardiac morbidity and mortality in developed countries, due to ageing populations and the increasing prevalence of comorbidities. While heart failure with reduced ejection fraction is dominated by left ventricular impairment, HFpEF results from a complex interplay of cardiac remodelling, peripheral circulation, and concomitant features including age, hypertension, obesity, and diabetes. In an important subset, however, HFpEF is subtended by specific diseases of the myocardium that are genetically determined, have distinct pathophysiology, and are increasingly amenable to targeted, innovative treatments. While each of these conditions is rare, they collectively represent a relevant subset within HFpEF cohorts, and their prompt recognition has major consequences for clinical practice, as access to dedicated, disease-specific treatments may radically change the quality of life and outcome. Furthermore, response to standard heart failure treatment will generally be modest for these individuals, whose inclusion in registries and trials may dilute the perceived efficacy of treatments targeting mainstream HFpEF. Finally, a better understanding of the molecular underpinnings of monogenic myocardial disease may help identify therapeutic targets and develop innovative treatments for selected HFpEF phenotypes of broader epidemiological relevance. The field of genetic cardiomyopathies is undergoing rapid transformation due to recent, groundbreaking advances in drug development, and deserves greater awareness within the heart failure community. The present review addressed existing and developing therapies for genetic causes of HFpEF, including hypertrophic cardiomyopathy, cardiac amyloidosis, and storage diseases, discussing their potential impact on management and their broader implications for our understanding of HFpEF at large.
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Affiliation(s)
- Iacopo Olivotto
- Department of Experimental and Clinical Medicine, University of Florence, Meyer University Children Hospital and Careggi University Hospital, Viale Pieraccini 24, 50139 Florence, Italy
| | - James E Udelson
- Division of Cardiology and The CardioVascular Center, Tufts Medical Center, and the Tufts University School of Medicine, 800 Washington St, Boston, MA 02111, USA
| | - Maurizio Pieroni
- Cardiology Department, Hospital San Donato, Via Pietro Nenni, 20 - 52100 Arezzo, Italy
| | - Claudio Rapezzi
- Cardiology Centre, University of Ferrara, Via Fossato di Mortara, 64/B - 44121 Ferrara, Italy.,Maria Cecilia Hospital, GVM Care & Research, Via Corriera, 1, 48033 Cotignola, Emilia-Romagna, Italy
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25
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Chai AC, Cui M, Chemello F, Li H, Chen K, Tan W, Atmanli A, McAnally JR, Zhang Y, Xu L, Liu N, Bassel-Duby R, Olson EN. Base editing correction of hypertrophic cardiomyopathy in human cardiomyocytes and humanized mice. Nat Med 2023; 29:401-411. [PMID: 36797478 PMCID: PMC10053064 DOI: 10.1038/s41591-022-02176-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 12/07/2022] [Indexed: 02/18/2023]
Abstract
The most common form of genetic heart disease is hypertrophic cardiomyopathy (HCM), which is caused by variants in cardiac sarcomeric genes and leads to abnormal heart muscle thickening. Complications of HCM include heart failure, arrhythmia and sudden cardiac death. The dominant-negative c.1208G>A (p.R403Q) pathogenic variant (PV) in β-myosin (MYH7) is a common and well-studied PV that leads to increased cardiac contractility and HCM onset. In this study we identify an adenine base editor and single-guide RNA system that can efficiently correct this human PV with minimal bystander editing and off-target editing at selected sites. We show that delivery of base editing components rescues pathological manifestations of HCM in induced pluripotent stem cell cardiomyocytes derived from patients with HCM and in a humanized mouse model of HCM. Our findings demonstrate the potential of base editing to treat inherited cardiac diseases and prompt the further development of adenine base editor-based therapies to correct monogenic variants causing cardiac disease.
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Affiliation(s)
- Andreas C Chai
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Miao Cui
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Francesco Chemello
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Hui Li
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Kenian Chen
- Quantitative Biomedical Research Center, Department of Population and Data Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Wei Tan
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Ayhan Atmanli
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - John R McAnally
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Yu Zhang
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Lin Xu
- Quantitative Biomedical Research Center, Department of Population and Data Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Ning Liu
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Rhonda Bassel-Duby
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Eric N Olson
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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26
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Lewis CTA, Ochala J. Myosin Heavy Chain as a Novel Key Modulator of Striated Muscle Resting State. Physiology (Bethesda) 2023; 38:0. [PMID: 36067133 DOI: 10.1152/physiol.00018.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
After years of intense research using structural, biological, and biochemical experimental procedures, it is clear that myosin molecules are essential for striated muscle contraction. However, this is just the tip of the iceberg of their function. Interestingly, it has been shown recently that these molecules (especially myosin heavy chains) are also crucial for cardiac and skeletal muscle resting state. In the present review, we first overview myosin heavy chain biochemical states and how they influence the consumption of ATP. We then detail how neighboring partner proteins including myosin light chains and myosin binding protein C intervene in such processes, modulating the ATP demand in health and disease. Finally, we present current experimental drugs targeting myosin ATP consumption and how they can treat muscle diseases.
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Affiliation(s)
| | - Julien Ochala
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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27
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Li J, Rahmani H, Abbasi Yeganeh F, Rastegarpouyani H, Taylor DW, Wood NB, Previs MJ, Iwamoto H, Taylor KA. Structure of the Flight Muscle Thick Filament from the Bumble Bee, Bombus ignitus, at 6 Å Resolution. Int J Mol Sci 2022; 24:377. [PMID: 36613818 PMCID: PMC9820631 DOI: 10.3390/ijms24010377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 12/12/2022] [Accepted: 12/13/2022] [Indexed: 12/28/2022] Open
Abstract
Four insect orders have flight muscles that are both asynchronous and indirect; they are asynchronous in that the wingbeat frequency is decoupled from the frequency of nervous stimulation and indirect in that the muscles attach to the thoracic exoskeleton instead of directly to the wing. Flight muscle thick filaments from two orders, Hemiptera and Diptera, have been imaged at a subnanometer resolution, both of which revealed a myosin tail arrangement referred to as “curved molecular crystalline layers”. Here, we report a thick filament structure from the indirect flight muscles of a third insect order, Hymenoptera, the Asian bumble bee Bombus ignitus. The myosin tails are in general agreement with previous determinations from Lethocerus indicus and Drosophila melanogaster. The Skip 2 region has the same unusual structure as found in Lethocerus indicus thick filaments, an α-helix discontinuity is also seen at Skip 4, but the orientation of the Skip 1 region on the surface of the backbone is less angled with respect to the filament axis than in the other two species. The heads are disordered as in Drosophila, but we observe no non-myosin proteins on the backbone surface that might prohibit the ordering of myosin heads onto the thick filament backbone. There are strong structural similarities among the three species in their non-myosin proteins within the backbone that suggest how one previously unassigned density in Lethocerus might be assigned. Overall, the structure conforms to the previously observed pattern of high similarity in the myosin tail arrangement, but differences in the non-myosin proteins.
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Affiliation(s)
- Jiawei Li
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4380, USA
| | - Hamidreza Rahmani
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4380, USA
| | - Fatemeh Abbasi Yeganeh
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4380, USA
| | - Hosna Rastegarpouyani
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4380, USA
| | - Dianne W. Taylor
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4380, USA
| | - Neil B. Wood
- Department of Molecular Physiology & Biophysics, University of Vermont, Larner College of Medicine, Burlington, VT 05405, USA
| | - Michael J. Previs
- Department of Molecular Physiology & Biophysics, University of Vermont, Larner College of Medicine, Burlington, VT 05405, USA
| | - Hiroyuki Iwamoto
- Scattering and Imaging Division, Japan Synchrotron Radiation Research Institute, SPring-8, Hyogo 679-5198, Japan
| | - Kenneth A. Taylor
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4380, USA
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28
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Martin AA, Thompson BR, Hahn D, Angulski ABB, Hosny N, Cohen H, Metzger JM. Cardiac Sarcomere Signaling in Health and Disease. Int J Mol Sci 2022; 23:16223. [PMID: 36555864 PMCID: PMC9782806 DOI: 10.3390/ijms232416223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/12/2022] [Accepted: 12/14/2022] [Indexed: 12/24/2022] Open
Abstract
The cardiac sarcomere is a triumph of biological evolution wherein myriad contractile and regulatory proteins assemble into a quasi-crystalline lattice to serve as the central point upon which cardiac muscle contraction occurs. This review focuses on the many signaling components and mechanisms of regulation that impact cardiac sarcomere function. We highlight the roles of the thick and thin filament, both as necessary structural and regulatory building blocks of the sarcomere as well as targets of functionally impactful modifications. Currently, a new focus emerging in the field is inter-myofilament signaling, and we discuss here the important mediators of this mechanism, including myosin-binding protein C and titin. As the understanding of sarcomere signaling advances, so do the methods with which it is studied. This is reviewed here through discussion of recent live muscle systems in which the sarcomere can be studied under intact, physiologically relevant conditions.
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Affiliation(s)
| | | | | | | | | | | | - Joseph M. Metzger
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
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29
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Rasicci DV, Tiwari P, Bodt SML, Desetty R, Sadler FR, Sivaramakrishnan S, Craig R, Yengo CM. Dilated cardiomyopathy mutation E525K in human beta-cardiac myosin stabilizes the interacting-heads motif and super-relaxed state of myosin. eLife 2022; 11:e77415. [PMID: 36422472 PMCID: PMC9691020 DOI: 10.7554/elife.77415] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 11/08/2022] [Indexed: 11/25/2022] Open
Abstract
The auto-inhibited, super-relaxed (SRX) state of cardiac myosin is thought to be crucial for regulating contraction, relaxation, and energy conservation in the heart. We used single ATP turnover experiments to demonstrate that a dilated cardiomyopathy (DCM) mutation (E525K) in human beta-cardiac myosin increases the fraction of myosin heads in the SRX state (with slow ATP turnover), especially in physiological ionic strength conditions. We also utilized FRET between a C-terminal GFP tag on the myosin tail and Cy3ATP bound to the active site of the motor domain to estimate the fraction of heads in the closed, interacting-heads motif (IHM); we found a strong correlation between the IHM and SRX state. Negative stain electron microscopy and 2D class averaging of the construct demonstrated that the E525K mutation increased the fraction of molecules adopting the IHM. Overall, our results demonstrate that the E525K DCM mutation may reduce muscle force and power by stabilizing the auto-inhibited SRX state. Our studies also provide direct evidence for a correlation between the SRX biochemical state and the IHM structural state in cardiac muscle myosin. Furthermore, the E525 residue may be implicated in crucial electrostatic interactions that modulate this conserved, auto-inhibited conformation of myosin.
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Affiliation(s)
- David V Rasicci
- Department of Cellular and Molecular Physiology, Penn State College of MedicineHersheyUnited States
| | - Prince Tiwari
- Department of Radiology, Division of Cell Biology and Imaging, UMass Chan Medical SchoolWorcesterUnited States
| | - Skylar ML Bodt
- Department of Cellular and Molecular Physiology, Penn State College of MedicineHersheyUnited States
| | - Rohini Desetty
- Department of Cellular and Molecular Physiology, Penn State College of MedicineHersheyUnited States
| | - Fredrik R Sadler
- Department of Genetics, Cell Biology, and Development, University of Minnesota Twin CitiesMinneapolisUnited States
| | - Sivaraj Sivaramakrishnan
- Department of Genetics, Cell Biology, and Development, University of Minnesota Twin CitiesMinneapolisUnited States
| | - Roger Craig
- Department of Radiology, Division of Cell Biology and Imaging, UMass Chan Medical SchoolWorcesterUnited States
| | - Christopher M Yengo
- Department of Cellular and Molecular Physiology, Penn State College of MedicineHersheyUnited States
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Mathai S, Williams L. Left ventricular outflow tract obstruction in hypertrophic cardiomyopathy and the impact of mavacamten. Ther Adv Chronic Dis 2022; 13:20406223221136074. [PMID: 36407022 PMCID: PMC9666864 DOI: 10.1177/20406223221136074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 10/14/2022] [Indexed: 08/14/2023] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is a common genetic disorder characterised by unexplained left ventricular hypertrophy. Left ventricular outflow tract obstruction is an integral component of the disease, often resulting in significant symptoms, but also carrying a risk of progression to heart failure and death. Advancements in our understanding of the pathophysiology of HCM have led to the development of new therapies targeting the molecular basis of the disease at the level of the cardiac sarcomere, the basic contractile apparatus of the myocardium. Myosin modulators are a novel class of small molecules which target cardiac myosins directly to modulate cardiac contractility. The myosin inhibitors present the first advancement in pharmacological management of obstructive HCM in almost 35 years, with a growing body of evidence for the safety, tolerability and efficacy of mavacamten, and to a lesser extent aficamten. The aim of this review is to summarise the current management of patients with obstructive HCM and review the most recent available data from clinical trials pertaining to myosin inhibition.
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Affiliation(s)
- Susan Mathai
- Department of Cardiology, Royal Papworth
Hospital NHS Foundation Trust, Cambridge, UK
| | - Lynne Williams
- Department of Cardiology, Royal Papworth
Hospital NHS Foundation Trust, Papworth Road, Cambridge Biomedical Campus,
Cambridge CB2 0AY, UK
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Forouzandehmehr M, Paci M, Koivumäki JT, Hyttinen J. Altered contractility in mutation-specific hypertrophic cardiomyopathy: A mechano-energetic in silico study with pharmacological insights. Front Physiol 2022; 13:1010786. [PMID: 36388127 PMCID: PMC9659818 DOI: 10.3389/fphys.2022.1010786] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 10/14/2022] [Indexed: 07/25/2023] Open
Abstract
Introduction: Mavacamten (MAVA), Blebbistatin (BLEB), and Omecamtiv mecarbil (OM) are promising drugs directly targeting sarcomere dynamics, with demonstrated efficacy against hypertrophic cardiomyopathy (HCM) in (pre)clinical trials. However, the molecular mechanism affecting cardiac contractility regulation, and the diseased cell mechano-energetics are not fully understood yet. Methods: We present a new metabolite-sensitive computational model of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) electromechanics to investigate the pathology of R403Q HCM mutation and the effect of MAVA, BLEB, and OM on the cell mechano-energetics. Results: We offer a mechano-energetic HCM calibration of the model, capturing the prolonged contractile relaxation due to R403Q mutation (∼33%), without assuming any further modifications such as an additional Ca2+ flux to the thin filaments. The HCM model variant correctly predicts the negligible alteration in ATPase activity in R403Q HCM condition compared to normal hiPSC-CMs. The simulated inotropic effects of MAVA, OM, and BLEB, along with the ATPase activities in the control and HCM model variant agree with in vitro results from different labs. The proposed model recapitulates the tension-Ca2+ relationship and action potential duration change due to 1 µM OM and 5 µM BLEB, consistently with in vitro data. Finally, our model replicates the experimental dose-dependent effect of OM and BLEB on the normalized isometric tension. Conclusion: This work is a step toward deep-phenotyping the mutation-specific HCM pathophysiology, manifesting as altered interfilament kinetics. Accordingly, the modeling efforts lend original insights into the MAVA, BLEB, and OM contributions to a new interfilament balance resulting in a cardioprotective effect.
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Månsson A, Rassier DE. Insights into Muscle Contraction Derived from the Effects of Small-Molecular Actomyosin-Modulating Compounds. Int J Mol Sci 2022; 23:ijms232012084. [PMID: 36292937 PMCID: PMC9603234 DOI: 10.3390/ijms232012084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Revised: 09/25/2022] [Accepted: 10/03/2022] [Indexed: 01/10/2023] Open
Abstract
Bottom-up mechanokinetic models predict ensemble function of actin and myosin based on parameter values derived from studies using isolated proteins. To be generally useful, e.g., to analyze disease effects, such models must also be able to predict ensemble function when actomyosin interaction kinetics are modified differently from normal. Here, we test this capability for a model recently shown to predict several physiological phenomena along with the effects of the small molecular compound blebbistatin. We demonstrate that this model also qualitatively predicts effects of other well-characterized drugs as well as varied concentrations of MgATP. However, the effects of one compound, amrinone, are not well accounted for quantitatively. We therefore systematically varied key model parameters to address this issue, leading to the increased amplitude of the second sub-stroke of the power stroke from 1 nm to 2.2 nm, an unchanged first sub-stroke (5.3−5.5 nm), and an effective cross-bridge attachment rate that more than doubled. In addition to better accounting for the effects of amrinone, the modified model also accounts well for normal physiological ensemble function. Moreover, a Monte Carlo simulation-based version of the model was used to evaluate force−velocity data from small myosin ensembles. We discuss our findings in relation to key aspects of actin−myosin operation mechanisms causing a non-hyperbolic shape of the force−velocity relationship at high loads. We also discuss remaining limitations of the model, including uncertainty of whether the cross-bridge elasticity is linear or not, the capability to account for contractile properties of very small actomyosin ensembles (<20 myosin heads), and the mechanism for requirements of a higher cross-bridge attachment rate during shortening compared to during isometric contraction.
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Affiliation(s)
- Alf Månsson
- Department of Chemistry and Biomedical Sciences, Linnaeus University, 391 82 Kalmar, Sweden
- Correspondence: ; Tel.: +46-708-866243
| | - Dilson E. Rassier
- Department of Kinesiology and Physical Education, McGill University, Montreal, QC H2W 1S4, Canada
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Reyes KRL, Bilgili G, Rader F. Mavacamten: A First-in-class Oral Modulator of Cardiac Myosin for the Treatment of Symptomatic Hypertrophic Obstructive Cardiomyopathy. Heart Int 2022; 16:91-98. [PMID: 36741099 PMCID: PMC9872784 DOI: 10.17925/hi.2022.16.2.91] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 08/04/2022] [Indexed: 12/25/2022] Open
Abstract
Hypertrophic cardiomyopathy is the most common monogenic cardiovascular disease that is caused by sarcomeric protein gene mutations. A hallmark of the most common form of the disease is outflow obstruction secondary to systolic narrowing of the left ventricular outflow tract from septal hypertrophy, mitral valve abnormalities and, most importantly, hyperdynamic contractility. Recent mechanistic studies have identified excessive myosin adenosine triphosphatase activation and actin-myosin cross-bridging as major underlying causes. These studies have led to the development of mavacamten, a first-in-class myosin adenosine triphosphatase inhibitor and the first specific therapy for hypertrophic obstructive cardiomyopathy. Preclinical and subsequent pivotal clinical studies have demonstrated the efficacy and safety of mavacamten. A remarkable improvement among treated patients in peak oxygen consumption, functional capacity, symptom relief and post-exercise left ventricular outflow tract gradient, along with dramatic reductions in heart failure biomarkers, suggests that this new medication will be transformative for the symptom management of hypertrophic obstructive cardiomyopathy. There is also hope and early evidence that mavacamten may delay or obviate the need for invasive septal reduction therapies. In this article, we review the current evidence for the efficacy and safety of mavacamten and highlight important considerations for its clinical use.
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Affiliation(s)
| | - Gizem Bilgili
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Florian Rader
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
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Kawana M, Spudich JA, Ruppel KM. Hypertrophic cardiomyopathy: Mutations to mechanisms to therapies. Front Physiol 2022; 13:975076. [PMID: 36225299 PMCID: PMC9548533 DOI: 10.3389/fphys.2022.975076] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 08/22/2022] [Indexed: 01/10/2023] Open
Abstract
Hypertrophic cardiomyopathy (HCM) affects more than 1 in 500 people in the general population with an extensive burden of morbidity in the form of arrhythmia, heart failure, and sudden death. More than 25 years since the discovery of the genetic underpinnings of HCM, the field has unveiled significant insights into the primary effects of these genetic mutations, especially for the myosin heavy chain gene, which is one of the most commonly mutated genes. Our group has studied the molecular effects of HCM mutations on human β-cardiac myosin heavy chain using state-of-the-art biochemical and biophysical tools for the past 10 years, combining insights from clinical genetics and structural analyses of cardiac myosin. The overarching hypothesis is that HCM-causing mutations in sarcomere proteins cause hypercontractility at the sarcomere level, and we have shown that an increase in the number of myosin molecules available for interaction with actin is a primary driver. Recently, two pharmaceutical companies have developed small molecule inhibitors of human cardiac myosin to counteract the molecular consequences of HCM pathogenesis. One of these inhibitors (mavacamten) has recently been approved by the FDA after completing a successful phase III trial in HCM patients, and the other (aficamten) is currently being evaluated in a phase III trial. Myosin inhibitors will be the first class of medication used to treat HCM that has both robust clinical trial evidence of efficacy and that targets the fundamental mechanism of HCM pathogenesis. The success of myosin inhibitors in HCM opens the door to finding other new drugs that target the sarcomere directly, as we learn more about the genetics and fundamental mechanisms of this disease.
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Affiliation(s)
- Masataka Kawana
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, United States,Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, United States
| | - James A. Spudich
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, United States
| | - Kathleen M. Ruppel
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, United States,*Correspondence: Kathleen M. Ruppel,
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Tamargo J, Tamargo M, Caballero R. Hypertrophic cardiomyopathy: an up-to-date snapshot of the clinical drug development pipeline. Expert Opin Investig Drugs 2022; 31:1027-1052. [PMID: 36062808 DOI: 10.1080/13543784.2022.2113374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Hypertrophic cardiomyopathy (HCM) is a complex cardiac disease with highly variable phenotypic expression and clinical course most often caused by sarcomeric gene mutations resulting in left ventricular hypertrophy, fibrosis, hypercontractility, and diastolic dysfunction. For almost 60 years, HCM has remained an orphan disease and still lacks a disease-specific treatment. AREAS COVERED This review summarizes recent preclinical and clinical trials with repurposed drugs and new emerging pharmacological and gene-based therapies for the treatment of HCM. EXPERT OPINION The off-label drugs routinely used alleviate symptoms but do not target the core pathophysiology of HCM or prevent or revert the phenotype. Recent advances in the genetics and pathophysiology of HCM led to the development of cardiac myosin adenosine triphosphatase inhibitors specifically directed to counteract the hypercontractility associated with HCM-causing mutations. Mavacamten, the first drug specifically developed for HCM successfully tested in a phase 3 trial, represents the major advance for the treatment of HCM. This opens new horizons for the development of novel drugs targeting HCM molecular substrates which hopefully modify the natural history of the disease. The role of current drugs in development and genetic-based approaches for the treatment of HCM are also discussed.
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Affiliation(s)
- Juan Tamargo
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense, Instituto de Investigación Sanitaria Gregorio Marañón, CIBERCV, 28040 Madrid, Spain
| | - María Tamargo
- Department of Cardiology, Hospital Universitario Gregorio Marañón, Instituto de Investigación Sanitaria Gregorio Marañón, CIBERCV, Doctor Esquerdo, 46, 28007 Madrid, Spain
| | - Ricardo Caballero
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense, Instituto de Investigación Sanitaria Gregorio Marañón, CIBERCV, 28040 Madrid, Spain
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36
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Myosins and MyomiR Network in Patients with Obstructive Hypertrophic Cardiomyopathy. Biomedicines 2022; 10:biomedicines10092180. [PMID: 36140281 PMCID: PMC9496008 DOI: 10.3390/biomedicines10092180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 08/30/2022] [Accepted: 09/01/2022] [Indexed: 11/17/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiomyopathy. The molecular mechanisms determining HCM phenotypes are incompletely understood. Myocardial biopsies were obtained from a group of patients with obstructive HCM (n = 23) selected for surgical myectomy and from 9 unused donor hearts (controls). A subset of tissue-abundant myectomy samples from HCM (n = 10) and controls (n = 6) was submitted to laser-capture microdissection to isolate cardiomyocytes. We investigated the relationship among clinical phenotype, cardiac myosin proteins (MyHC6, MyHC7, and MyHC7b) measured by optimized label-free mass spectrometry, the relative genes (MYH7, MYH7B and MYLC2), and the MyomiR network (myosin-encoded microRNA (miRs) and long-noncoding RNAs (Mhrt)) measured using RNA sequencing and RT-qPCR. MyHC6 was lower in HCM vs. controls, whilst MyHC7, MyHC7b, and MyLC2 were comparable. MYH7, MYH7B, and MYLC2 were higher in HCM whilst MYH6, miR-208a, miR-208b, miR-499 were comparable in HCM and controls. These results are compatible with defective transcription by active genes in HCM. Mhrt and two miR-499-target genes, SOX6 and PTBP3, were upregulated in HCM. The presence of HCM-associated mutations correlated with PTBP3 in myectomies and with SOX6 in cardiomyocytes. Additionally, iPSC-derived cardiomyocytes, transiently transfected with either miR-208a or miR-499, demonstrated a time-dependent relationship between MyomiRs and myosin genes. The transfection end-stage pattern was at least in part similar to findings in HCM myectomies. These data support uncoupling between myosin protein/genes and a modulatory role for the myosin/MyomiR network in the HCM myocardium, possibly contributing to phenotypic diversity and providing putative therapeutic targets.
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37
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McMillan SN, Scarff CA. Cryo-electron microscopy analysis of myosin at work and at rest. Curr Opin Struct Biol 2022; 75:102391. [DOI: 10.1016/j.sbi.2022.102391] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 04/18/2022] [Accepted: 04/22/2022] [Indexed: 01/01/2023]
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Edelberg JM, Sehnert AJ, Mealiffe ME, Del Rio CL, McDowell R. The Impact of Mavacamten on the Pathophysiology of Hypertrophic Cardiomyopathy: A Narrative Review. Am J Cardiovasc Drugs 2022; 22:497-510. [PMID: 35435607 PMCID: PMC9467968 DOI: 10.1007/s40256-022-00532-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/24/2022] [Indexed: 11/25/2022]
Abstract
Hypertrophic cardiomyopathy (HCM) is a chronic, progressive disease of the cardiomyocyte with a diverse and heterogeneous clinical presentation and course. This diversity and heterogeneity have added to the complexity of modeling the pathophysiological pathways that contribute to the disease burden. The development of novel therapeutic approaches targeting precise mechanisms within the underlying biology of HCM provides a tool to model and test these pathways. Here, we integrate the results of clinical observations with mavacamten, an allosteric, selective, and reversible inhibitor of cardiac myosin, the motor unit of the sarcomere, to develop an integrated pathophysiological pathway model of HCM, confirming the key role of excess sarcomeric activity. This model may serve as a foundation to understand the role of HCM pathophysiological pathways in the clinical presentation of the disease, and how a targeted therapeutic intervention capable of normalizing sarcomeric activity and repopulating low-energy utilization states may reduce the impact of these pathways in HCM and potentially related disease states.
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Affiliation(s)
- Jay M Edelberg
- Clinical Development, Cardiovascular Global Drug Development, MyoKardia, Inc., A Wholly Owned Subsidiary of Bristol Myers Squibb, Brisbane, CA, USA
| | - Amy J Sehnert
- Clinical Development, Cardiovascular Global Drug Development, MyoKardia, Inc., A Wholly Owned Subsidiary of Bristol Myers Squibb, Brisbane, CA, USA
| | - Matthew E Mealiffe
- Early Clinical Development, MyoKardia, Inc., A Wholly Owned Subsidiary of Bristol Myers Squibb, Brisbane, CA, USA
| | - Carlos L Del Rio
- Clinical Development, Cardiovascular Global Drug Development, MyoKardia, Inc., A Wholly Owned Subsidiary of Bristol Myers Squibb, Brisbane, CA, USA
| | - Robert McDowell
- Research & Early Development, MyoKardia, Inc., A Wholly Owned Subsidiary of Bristol Myers Squibb, 1000 Sierra Point Parkway, Brisbane, CA, 94005, USA.
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39
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Hassoun R, Erdmann C, Schmitt S, Fujita-Becker S, Mügge A, Schröder RR, Geyer M, Borbor M, Jaquet K, Hamdani N, Mannherz HG. Functional Characterization of Cardiac Actin Mutants Causing Hypertrophic (p.A295S) and Dilated Cardiomyopathy (p.R312H and p.E361G). Int J Mol Sci 2022; 23:ijms23084465. [PMID: 35457283 PMCID: PMC9024677 DOI: 10.3390/ijms23084465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 04/15/2022] [Accepted: 04/15/2022] [Indexed: 11/16/2022] Open
Abstract
Human wild type (wt) cardiac α-actin and its mutants p.A295S or p.R312H and p.E361G correlated with hypertrophic or dilated cardiomyopathy, respectively, were expressed by using the baculovirus/Sf21 insect cell system. The c-actin variants inhibited DNase I, indicating maintenance of their native state. Electron microscopy showed the formation of normal appearing actin filaments though they showed mutant specific differences in length and straightness correlating with their polymerization rates. TRITC-phalloidin staining showed that p.A295S and p.R312H exhibited reduced and the p.E361G mutant increased lengths of their formed filaments. Decoration of c-actins with cardiac tropomyosin (cTm) and troponin (cTn) conveyed Ca2+-sensitivity of the myosin-S1 ATPase stimulation, which was higher for the HCM p.A295S mutant and lower for the DCM p.R312H and p.E361G mutants than for wt c-actin. The lower Ca2+-sensitivity of myosin-S1 stimulation by both DCM actin mutants was corrected by the addition of levosimendan. Ca2+-dependency of the movement of pyrene-labeled cTm along polymerized c-actin variants decorated with cTn corresponded to the relations observed for the myosin-S1 ATPase stimulation though shifted to lower Ca2+-concentrations. The N-terminal C0C2 domain of cardiac myosin-binding protein-C increased the Ca2+-sensitivity of the pyrene-cTM movement of bovine, recombinant wt, p.A295S, and p.E361G c-actins, but not of the p.R312H mutant, suggesting decreased affinity to cTm.
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Affiliation(s)
- Roua Hassoun
- Institut für Forschung und Lehre (IFL), Molecular and Experimental Cardiology, Medical Faculty, Ruhr University Bochum, D-44791 Bochum, Germany; (R.H.); (A.M.); (K.J.)
- Department of Cardiology, St. Josef-Hospital, Medical Faculty, Ruhr University Bochum, D-44791 Bochum, Germany
| | - Constanze Erdmann
- Department of Anatomy and Molecular Embryology, Medical Faculty, Ruhr-University Bochum, D-44780 Bochum, Germany;
| | - Sebastian Schmitt
- Institute of Structural Biology, University of Bonn, D-53127 Bonn, Germany; (S.S.); (M.G.)
| | - Setsuko Fujita-Becker
- Cryoelectron Microscopy, BioQuant, Medical Faculty, University of Heidelberg, D-69120 Heidelberg, Germany; (S.F.-B.); (R.R.S.)
| | - Andreas Mügge
- Institut für Forschung und Lehre (IFL), Molecular and Experimental Cardiology, Medical Faculty, Ruhr University Bochum, D-44791 Bochum, Germany; (R.H.); (A.M.); (K.J.)
- Department of Cardiology, St. Josef-Hospital, Medical Faculty, Ruhr University Bochum, D-44791 Bochum, Germany
| | - Rasmus R. Schröder
- Cryoelectron Microscopy, BioQuant, Medical Faculty, University of Heidelberg, D-69120 Heidelberg, Germany; (S.F.-B.); (R.R.S.)
| | - Matthias Geyer
- Institute of Structural Biology, University of Bonn, D-53127 Bonn, Germany; (S.S.); (M.G.)
| | - Mina Borbor
- Department of Neurology, University Hospital Essen, D-45147 Essen, Germany;
| | - Kornelia Jaquet
- Institut für Forschung und Lehre (IFL), Molecular and Experimental Cardiology, Medical Faculty, Ruhr University Bochum, D-44791 Bochum, Germany; (R.H.); (A.M.); (K.J.)
- Department of Cardiology, St. Josef-Hospital, Medical Faculty, Ruhr University Bochum, D-44791 Bochum, Germany
| | - Nazha Hamdani
- Institut für Forschung und Lehre (IFL), Molecular and Experimental Cardiology, Medical Faculty, Ruhr University Bochum, D-44791 Bochum, Germany; (R.H.); (A.M.); (K.J.)
- Department of Cardiology, St. Josef-Hospital, Medical Faculty, Ruhr University Bochum, D-44791 Bochum, Germany
- Correspondence: (N.H.); (H.G.M.); Tel.: +49-234-32-29412 (N.H.); Fax: +49-234-32-14040 (N.H.); +49-234-32-14474 (H.G.M.)
| | - Hans Georg Mannherz
- Institut für Forschung und Lehre (IFL), Molecular and Experimental Cardiology, Medical Faculty, Ruhr University Bochum, D-44791 Bochum, Germany; (R.H.); (A.M.); (K.J.)
- Department of Anatomy and Molecular Embryology, Medical Faculty, Ruhr-University Bochum, D-44780 Bochum, Germany;
- Correspondence: (N.H.); (H.G.M.); Tel.: +49-234-32-29412 (N.H.); Fax: +49-234-32-14040 (N.H.); +49-234-32-14474 (H.G.M.)
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Ovejero JG, Fusi L, Park-Holohan SJ, Ghisleni A, Narayanan T, Irving M, Brunello E. Cooling intact and demembranated trabeculae from rat heart releases myosin motors from their inhibited conformation. J Gen Physiol 2022; 154:212988. [PMID: 35089319 PMCID: PMC8823665 DOI: 10.1085/jgp.202113029] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 01/10/2022] [Indexed: 12/26/2022] Open
Abstract
Myosin filament–based regulation supplements actin filament–based regulation to control the strength and speed of contraction in heart muscle. In diastole, myosin motors form a folded helical array that inhibits actin interaction; during contraction, they are released from that array. A similar structural transition has been observed in mammalian skeletal muscle, in which cooling below physiological temperature has been shown to reproduce some of the structural features of the activation of myosin filaments during active contraction. Here, we used small-angle x-ray diffraction to characterize the structural changes in the myosin filaments associated with cooling of resting and relaxed trabeculae from the right ventricle of rat hearts from 39°C to 7°C. In intact quiescent trabeculae, cooling disrupted the folded helical conformation of the myosin motors and induced extension of the filament backbone, as observed in the transition from diastole to peak systolic force at 27°C. Demembranation of trabeculae in relaxing conditions induced expansion of the filament lattice, but the structure of the myosin filaments was mostly preserved at 39°C. Cooling of relaxed demembranated trabeculae induced changes in motor conformation and filament structure similar to those observed in intact quiescent trabeculae. Osmotic compression of the filament lattice to restore its spacing to that of intact trabeculae at 39°C stabilized the helical folded state against disruption by cooling. The myosin filament structure and motor conformation of intact trabeculae at 39°C were largely preserved in demembranated trabeculae at 27°C or above in the presence of Dextran, allowing the physiological mechanisms of myosin filament–based regulation to be studied in those conditions.
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Affiliation(s)
- Jesus G Ovejero
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK
| | - Luca Fusi
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK.,Centre for Human and Applied Physiological Sciences, King's College London, London, UK
| | - So-Jin Park-Holohan
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK
| | - Andrea Ghisleni
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK
| | | | - Malcolm Irving
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK
| | - Elisabetta Brunello
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK
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Suay-Corredera C, Alegre-Cebollada J. The mechanics of the heart: zooming in on hypertrophic cardiomyopathy and cMyBP-C. FEBS Lett 2022; 596:703-746. [PMID: 35224729 DOI: 10.1002/1873-3468.14301] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 01/10/2022] [Accepted: 01/14/2022] [Indexed: 11/10/2022]
Abstract
Hypertrophic cardiomyopathy (HCM), a disease characterized by cardiac muscle hypertrophy and hypercontractility, is the most frequently inherited disorder of the heart. HCM is mainly caused by variants in genes encoding proteins of the sarcomere, the basic contractile unit of cardiomyocytes. The most frequently mutated among them is MYBPC3, which encodes cardiac myosin-binding protein C (cMyBP-C), a key regulator of sarcomere contraction. In this review, we summarize clinical and genetic aspects of HCM and provide updated information on the function of the healthy and HCM sarcomere, as well as on emerging therapeutic options targeting sarcomere mechanical activity. Building on what is known about cMyBP-C activity, we examine different pathogenicity drivers by which MYBPC3 variants can cause disease, focussing on protein haploinsufficiency as a common pathomechanism also in nontruncating variants. Finally, we discuss recent evidence correlating altered cMyBP-C mechanical properties with HCM development.
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42
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Molecular basis of force-pCa relation in MYL2 cardiomyopathy mice: Role of the super-relaxed state of myosin. Proc Natl Acad Sci U S A 2022; 119:2110328119. [PMID: 35177471 PMCID: PMC8872785 DOI: 10.1073/pnas.2110328119] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2022] [Indexed: 01/22/2023] Open
Abstract
Many forms of cardiomyopathy manifest with changes in sarcomeric structure, function, and energetics. We used small-angle X-ray diffraction and myosin super-relaxed (SRX) state approaches to investigate the mechanisms underlying the clinical phenotypes associated with HCM-related D166V (aspartate-to-valine) and DCM-linked D94A (aspartate-to-alanine) mutations in the cardiac myosin RLC (MYL2 gene). Modulation of myosin function through dysregulation of the SRX state was closely coupled with structural rearrangements and the Ca2+ dependence of force development in HCM–D166V mice. The DCM–D94A model favored the SRX state without altering structure/force–pCa relationships. Understanding the regulation of SRX ↔ DRX equilibrium in the normal heart and how it is changed in heart disease may advance future therapeutics of patients suffering from the mutated MYL2 gene. In this study, we investigated the role of the super-relaxed (SRX) state of myosin in the structure–function relationship of sarcomeres in the hearts of mouse models of cardiomyopathy-bearing mutations in the human ventricular regulatory light chain (RLC, MYL2 gene). Skinned papillary muscles from hypertrophic (HCM–D166V) and dilated (DCM–D94A) cardiomyopathy models were subjected to small-angle X-ray diffraction simultaneously with isometric force measurements to obtain the interfilament lattice spacing and equatorial intensity ratios (I11/I10) together with the force-pCa relationship over a full range of [Ca2+] and at a sarcomere length of 2.1 μm. In parallel, we studied the effect of mutations on the ATP-dependent myosin energetic states. Compared with wild-type (WT) and DCM–D94A mice, HCM–D166V significantly increased the Ca2+ sensitivity of force and left shifted the I11/I10-pCa relationship, indicating an apparent movement of HCM–D166V cross-bridges closer to actin-containing thin filaments, thereby allowing for their premature Ca2+ activation. The HCM–D166V model also disrupted the SRX state and promoted an SRX-to-DRX (super-relaxed to disordered relaxed) transition that correlated with an HCM-linked phenotype of hypercontractility. While this dysregulation of SRX ↔ DRX equilibrium was consistent with repositioning of myosin motors closer to the thin filaments and with increased force-pCa dependence for HCM–D166V, the DCM–D94A model favored the energy-conserving SRX state, but the structure/function–pCa data were similar to WT. Our results suggest that the mutation-induced redistribution of myosin energetic states is one of the key mechanisms contributing to the development of complex clinical phenotypes associated with human HCM–D166V and DCM–D94A mutations.
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Critical Evaluation of Current Hypotheses for the Pathogenesis of Hypertrophic Cardiomyopathy. Int J Mol Sci 2022; 23:ijms23042195. [PMID: 35216312 PMCID: PMC8880276 DOI: 10.3390/ijms23042195] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/07/2022] [Accepted: 02/14/2022] [Indexed: 02/04/2023] Open
Abstract
Hereditary hypertrophic cardiomyopathy (HCM), due to mutations in sarcomere proteins, occurs in more than 1/500 individuals and is the leading cause of sudden cardiac death in young people. The clinical course exhibits appreciable variability. However, typically, heart morphology and function are normal at birth, with pathological remodeling developing over years to decades, leading to a phenotype characterized by asymmetric ventricular hypertrophy, scattered fibrosis and myofibrillar/cellular disarray with ultimate mechanical heart failure and/or severe arrhythmias. The identity of the primary mutation-induced changes in sarcomere function and how they trigger debilitating remodeling are poorly understood. Support for the importance of mutation-induced hypercontractility, e.g., increased calcium sensitivity and/or increased power output, has been strengthened in recent years. However, other ideas that mutation-induced hypocontractility or non-uniformities with contractile instabilities, instead, constitute primary triggers cannot yet be discarded. Here, we review evidence for and criticism against the mentioned hypotheses. In this process, we find support for previous ideas that inefficient energy usage and a blunted Frank–Starling mechanism have central roles in pathogenesis, although presumably representing effects secondary to the primary mutation-induced changes. While first trying to reconcile apparently diverging evidence for the different hypotheses in one unified model, we also identify key remaining questions and suggest how experimental systems that are built around isolated primarily expressed proteins could be useful.
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Bang ML, Bogomolovas J, Chen J. Understanding the molecular basis of cardiomyopathy. Am J Physiol Heart Circ Physiol 2022; 322:H181-H233. [PMID: 34797172 PMCID: PMC8759964 DOI: 10.1152/ajpheart.00562.2021] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/16/2021] [Accepted: 11/16/2021] [Indexed: 02/03/2023]
Abstract
Inherited cardiomyopathies are a major cause of mortality and morbidity worldwide and can be caused by mutations in a wide range of proteins located in different cellular compartments. The present review is based on Dr. Ju Chen's 2021 Robert M. Berne Distinguished Lectureship of the American Physiological Society Cardiovascular Section, in which he provided an overview of the current knowledge on the cardiomyopathy-associated proteins that have been studied in his laboratory. The review provides a general summary of the proteins in different compartments of cardiomyocytes associated with cardiomyopathies, with specific focus on the proteins that have been studied in Dr. Chen's laboratory.
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Affiliation(s)
- Marie-Louise Bang
- Institute of Genetic and Biomedical Research (IRGB), National Research Council (CNR), Milan Unit, Milan, Italy
- IRCCS Humanitas Research Hospital, Rozzano (Milan), Italy
| | - Julius Bogomolovas
- Division of Cardiovascular Medicine, Department of Medicine Cardiology, University of California, San Diego, La Jolla, California
| | - Ju Chen
- Division of Cardiovascular Medicine, Department of Medicine Cardiology, University of California, San Diego, La Jolla, California
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Heissler SM, Arora AS, Billington N, Sellers JR, Chinthalapudi K. Cryo-EM structure of the autoinhibited state of myosin-2. SCIENCE ADVANCES 2021; 7:eabk3273. [PMID: 34936462 PMCID: PMC8694606 DOI: 10.1126/sciadv.abk3273] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 11/05/2021] [Indexed: 05/20/2023]
Abstract
We solved the near-atomic resolution structure of smooth muscle myosin-2 in the autoinhibited state (10S) using single-particle cryo–electron microscopy. The 3.4-Å structure reveals the precise molecular architecture of 10S and the structural basis for myosin-2 regulation. We reveal the position of the phosphorylation sites that control myosin autoinhibition and activation by phosphorylation of the regulatory light chain. Further, we present a previously unidentified conformational state in myosin-2 that traps ADP and Pi produced by the hydrolysis of ATP in the active site. This noncanonical state represents a branch of the myosin enzyme cycle and explains the autoinhibition of the enzyme function of 10S along with its reduced affinity for actin. Together, our structure defines the molecular mechanisms that drive 10S formation, stabilization, and relief by phosphorylation of the regulatory light chain.
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Affiliation(s)
- Sarah M. Heissler
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Amandeep S. Arora
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Neil Billington
- Laboratory of Molecular Physiology, National Heart, Lung, and Blood Institute, Bethesda, MD, USA
| | - James R. Sellers
- Laboratory of Molecular Physiology, National Heart, Lung, and Blood Institute, Bethesda, MD, USA
| | - Krishna Chinthalapudi
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University College of Medicine, Columbus, OH, USA
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Desai N, Xie J, Wang Y, Sutton MB, Whang J, Fine JT, Garrison LP. Projecting the Long-term Clinical Value of Mavacamten for the Treatment of Obstructive Hypertrophic Cardiomyopathy in the United States: An Assessment of Net Health Benefit. Clin Ther 2021; 44:52-66.e2. [PMID: 34911641 DOI: 10.1016/j.clinthera.2021.11.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/05/2021] [Accepted: 11/13/2021] [Indexed: 11/27/2022]
Abstract
PURPOSE The aim of the study was to project the long-term net health benefits of mavacamten for the treatment of symptomatic obstructive hypertrophic cardiomyopathy (HCM) in the United States. METHODS A Markov model with 4 mutually exclusive health states (New York Heart Association [NYHA] functional classes I, II, and III/IV and death) was developed to project the life-years (LYs) and quality-adjusted life-years (QALYs) over a lifetime horizon for patients with symptomatic obstructive HCM receiving mavacamten with or without β-blocker (BB) or calcium channel blocker (CCB) monotherapy or placebo with or without BB or CCB monotherapy. The model simulated a patient cohort with a starting age of 59 years and 41% women. Transition probabilities across NYHA functional classes were estimated using data from the Phase III Clinical Study to Evaluate Mavacamten (MYK-461) in Adults With Symptomatic Obstructive Hypertrophic Cardiomyopathy (EXPLORER-HCM) and the EXPLORER long-term extension (EXPLORER-LTE) cohort from the Long-term Safety Extension Study of Mavacamten in Adults who Have Completed MAVERICK-HCM or EXPLORER-HCM (MAVA-LTE) trial and were extrapolated after week 30. The mortality risks of NYHA functional class I were assumed to be the age- and sex-specific mortality risks of the US general population. The mortality risks for NYHA class II and III/IV were estimated using those for class I in conjunction with the relative mortality risks derived using patients with obstructive HCM from a large real-world registry. Health state utilities for each treatment were estimated from EXPLORER-HCM. Both LYs and QALYs were aggregated over a lifetime for each treatment arm, discounted at 3% annually, and compared between the 2 arms. Sensitivity analyses were conducted to evaluate the robustness of the model findings. FINDINGS Over a lifetime, treatment with mavacamten with or without BB or CCB monotherapy was associated with 3.67 incremental LYs compared with placebo with or without BB or CCB monotherapy (13.00 vs 9.33 LYs). Compared with individuals in the placebo group, patients in the mavacamten group were projected to spend 6.17 additional LYs in NYHA functional class I and 0.04 and 2.46 fewer LYs in NYHA functional classes II and III/IV, respectively. With utilities incorporated, mavacamten with or without BB or CCB monotherapy was associated with 4.17 additional QALYs compared with placebo with or without BB or CCB monotherapy (11.74 vs 7.57 QALYs). In the sensitivity analyses, incremental benefits ranged from 1.55 to 6.21 LYs and from 2.48 to 6.19 QALYs across the scenarios. IMPLICATIONS This model projected substantial net health benefits associated with mavacamten for symptomatic obstructive HCM owing to improved patient survival and quality of life. The projected QALY gain underscored the likely long-term clinical value of mavacamten in symptomatic obstructive HCM.
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Affiliation(s)
- Nihar Desai
- Yale University School of Medicine, New Haven, Connecticut
| | - Jipan Xie
- Analysis Group Inc, Los Angeles, California
| | - Yan Wang
- Analysis Group Inc, Los Angeles, California
| | - Megan B Sutton
- MyoKardia Inc, a wholly owned subsidiary of Bristol Myers Squibb, Brisbane, California
| | - John Whang
- Bristol Myers Squibb, Lawrence Township, New Jersey
| | - Jennifer T Fine
- MyoKardia Inc, a wholly owned subsidiary of Bristol Myers Squibb, Brisbane, California
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Two Classes of Myosin Inhibitors, Para-nitroblebbistatin and Mavacamten, Stabilize β-Cardiac Myosin in Different Structural and Functional States. J Mol Biol 2021; 433:167295. [PMID: 34627791 DOI: 10.1016/j.jmb.2021.167295] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 09/28/2021] [Accepted: 10/01/2021] [Indexed: 11/20/2022]
Abstract
In addition to a conventional relaxed state, a fraction of myosins in the cardiac muscle exists in a low-energy consuming super-relaxed (SRX) state, which is kept as a reserve pool that may be engaged under sustained increased cardiac demand. The conventional relaxed and the super-relaxed states are widely assumed to correspond to a structure where myosin heads are in an open configuration, free to interact with actin, and a closed configuration, inhibiting binding to actin, respectively. Disruption of the myosin SRX population is an emerging model in different heart diseases, such as hypertrophic cardiomyopathy, which results in excessive muscle contraction, and stabilizing them using myosin inhibitors is budding as an attractive therapeutic strategy. Here we examined the structure-function relationships of two myosin ATPase inhibitors, mavacamten and para-nitroblebbistatin, and found that binding of mavacamten at a site different than para-nitroblebbistatin populates myosin into the SRX state. Para-nitroblebbistatin, binding to a distal pocket to the myosin lever arm near the nucleotide-binding site, does not affect the usual myosin SRX state but instead appears to render myosin into a new, perhaps much more inhibited, 'ultra-relaxed' state. X-ray scattering-based rigid body modeling shows that both mavacamten and para-nitroblebbistatin induce novel conformations in human β-cardiac heavy meromyosin that diverge significantly from the hypothetical open and closed states, and furthermore, mavacamten treatment causes greater compaction than para-nitroblebbistatin. Taken together, we conclude that mavacamten and para-nitroblebbistatin stabilize myosin in different structural states, and such states may give rise to different functional energy-sparing states.
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Burghardt TP. Natural variant frequencies across domains from different sarcomere proteins cross-correlate to identify inter-protein contacts associated with cardiac muscle function and disease. MOLECULAR BIOMEDICINE 2021; 2:35. [PMID: 35006463 PMCID: PMC8607394 DOI: 10.1186/s43556-021-00056-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 09/23/2021] [Indexed: 12/15/2022] Open
Abstract
Coordinated sarcomere proteins produce contraction force for muscle shortening. In human ventriculum they include the cardiac myosin motor (βmys), repetitively converting ATP free energy into work, and myosin binding protein C (MYBPC3) that in complex with βmys is regulatory. Single nucleotide variants (SNVs) causing hereditary heart diseases frequently target this protein pair. The βmys/MYBPC3 complex models a regulated motor and is used here to study how the proteins couple. SNVs in βmys or MYBPC3 survey human populations worldwide. Their protein expression modifies domain structure affecting phenotype and pathogenicity outcomes. When the SNV modified domain locates to inter-protein contacts it could affect complex coordination. Domains involved, one in βmys the other in MYBPC3, form coordinated domains (co-domains). Co-domain bilateral structure implies the possibility for a shared impact from SNV modification in either domain suggesting a correlated response to a common perturbation could identify their location. Genetic divergence over human populations is proposed to perturb SNV probability coupling that is detected by cross-correlation in 2D correlation genetics (2D-CG). SNV probability data and 2D-CG identify three critical sites, two in MYBPC3 with links to several domains across the βmys motor, and, one in βmys with links to the MYBPC3 regulatory domain. MYBPC3 sites are hinges sterically enabling regulatory interactions with βmys. The βmys site is the actin binding C-loop (residues 359-377). The C-loop is a trigger for actin-activated myosin ATPase and a contraction velocity modulator. Co-domain identification implies their spatial proximity suggesting a novel approach for in vivo protein complex structure determination.
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Affiliation(s)
- Thomas P Burghardt
- Department of Biochemistry and Molecular Biology, Mayo Clinic Rochester, 200 First St. SW, Rochester, MN, 55905, USA.
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Barrick SK, Greenberg MJ. Cardiac myosin contraction and mechanotransduction in health and disease. J Biol Chem 2021; 297:101297. [PMID: 34634306 PMCID: PMC8559575 DOI: 10.1016/j.jbc.2021.101297] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 10/06/2021] [Accepted: 10/07/2021] [Indexed: 12/17/2022] Open
Abstract
Cardiac myosin is the molecular motor that powers heart contraction by converting chemical energy from ATP hydrolysis into mechanical force. The power output of the heart is tightly regulated to meet the physiological needs of the body. Recent multiscale studies spanning from molecules to tissues have revealed complex regulatory mechanisms that fine-tune cardiac contraction, in which myosin not only generates power output but also plays an active role in its regulation. Thus, myosin is both shaped by and actively involved in shaping its mechanical environment. Moreover, these studies have shown that cardiac myosin-generated tension affects physiological processes beyond muscle contraction. Here, we review these novel regulatory mechanisms, as well as the roles that myosin-based force generation and mechanotransduction play in development and disease. We describe how key intra- and intermolecular interactions contribute to the regulation of myosin-based contractility and the role of mechanical forces in tuning myosin function. We also discuss the emergence of cardiac myosin as a drug target for diseases including heart failure, leading to the discovery of therapeutics that directly tune myosin contractility. Finally, we highlight some of the outstanding questions that must be addressed to better understand myosin's functions and regulation, and we discuss prospects for translating these discoveries into precision medicine therapeutics targeting contractility and mechanotransduction.
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Affiliation(s)
- Samantha K Barrick
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Michael J Greenberg
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA.
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Erdmann C, Hassoun R, Schmitt S, Kikuti C, Houdusse A, Mazur AJ, Mügge A, Hamdani N, Geyer M, Jaquet K, Mannherz HG. Integration of Cardiac Actin Mutants Causing Hypertrophic (p.A295S) and Dilated Cardiomyopathy (p.R312H and p.E361G) into Cellular Structures. Antioxidants (Basel) 2021; 10:antiox10071082. [PMID: 34356314 PMCID: PMC8301065 DOI: 10.3390/antiox10071082] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 06/26/2021] [Accepted: 06/30/2021] [Indexed: 02/03/2023] Open
Abstract
The human mutant cardiac α-actins p.A295S or p.R312H and p.E361G, correlated with hypertrophic or dilated cardiomyopathy, respectively, were expressed by the baculovirus/Sf21 insect cell system and purified to homogeneity. The purified cardiac actins maintained their native state but showed differences in Ca2+-sensitivity to stimulate the myosin-subfragment1 ATPase. Here we analyzed the interactions of these c-actins with actin-binding and -modifying proteins implicated in cardiomyocyte differentiation. We demonstrate that Arp2/3 complex and the formin mDia3 stimulated the polymerization rate and extent of the c-actins, albeit to different degrees. In addition, we tested the effect of the MICAL-1 monooxygenase, which modifies the supramolecular actin organization during development and adaptive processes. MICAL-1 oxidized these c-actin variants and induced their de-polymerization, albeit at different rates. Transfection experiments using MDCK cells demonstrated the preferable incorporation of wild type and p.A295S c-actins into their microfilament system but of p.R312H and p.E361G actins into the submembranous actin network. Transduction of neonatal rat cardiomyocytes with adenoviral constructs coding HA-tagged c-actin variants showed their incorporation into microfilaments after one day in culture and thereafter into thin filaments of nascent sarcomeric structures at their plus ends (Z-lines) except the p.E361G mutant, which preferentially incorporated at the minus ends.
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Affiliation(s)
- Constanze Erdmann
- Department of Anatomy and Molecular Embryology, Medical Faculty, Ruhr-University Bochum, D-44780 Bochum, Germany;
| | - Roua Hassoun
- Institut für Forschung und Lehre (IFL), Molecular and Experimental Cardiology, Ruhr University Bochum, D-44780 Bochum, Germany; (R.H.); (A.M.); (N.H.); (K.J.)
- Department of Cardiology, St. Josef-Hospital and Bergmannsheil, Ruhr University Bochum, D-44780 Bochum, Germany
| | - Sebastian Schmitt
- Institute of Structural Biology, University of Bonn, D-53127 Bonn, Germany; (S.S.); (M.G.)
| | - Carlos Kikuti
- Institut Curie, Structural Motility Team, F-75005 Paris, France; (C.K.); (A.H.)
| | - Anne Houdusse
- Institut Curie, Structural Motility Team, F-75005 Paris, France; (C.K.); (A.H.)
| | - Antonina J. Mazur
- Department of Cell Pathology, Faculty of Biotechnology, University of Wroclaw, Pl-50-383 Wroclaw, Poland;
| | - Andreas Mügge
- Institut für Forschung und Lehre (IFL), Molecular and Experimental Cardiology, Ruhr University Bochum, D-44780 Bochum, Germany; (R.H.); (A.M.); (N.H.); (K.J.)
- Department of Cardiology, St. Josef-Hospital and Bergmannsheil, Ruhr University Bochum, D-44780 Bochum, Germany
| | - Nazha Hamdani
- Institut für Forschung und Lehre (IFL), Molecular and Experimental Cardiology, Ruhr University Bochum, D-44780 Bochum, Germany; (R.H.); (A.M.); (N.H.); (K.J.)
- Department of Cardiology, St. Josef-Hospital and Bergmannsheil, Ruhr University Bochum, D-44780 Bochum, Germany
| | - Matthias Geyer
- Institute of Structural Biology, University of Bonn, D-53127 Bonn, Germany; (S.S.); (M.G.)
| | - Kornelia Jaquet
- Institut für Forschung und Lehre (IFL), Molecular and Experimental Cardiology, Ruhr University Bochum, D-44780 Bochum, Germany; (R.H.); (A.M.); (N.H.); (K.J.)
- Department of Cardiology, St. Josef-Hospital and Bergmannsheil, Ruhr University Bochum, D-44780 Bochum, Germany
| | - Hans Georg Mannherz
- Department of Anatomy and Molecular Embryology, Medical Faculty, Ruhr-University Bochum, D-44780 Bochum, Germany;
- Institut für Forschung und Lehre (IFL), Molecular and Experimental Cardiology, Ruhr University Bochum, D-44780 Bochum, Germany; (R.H.); (A.M.); (N.H.); (K.J.)
- Department of Cardiology, St. Josef-Hospital and Bergmannsheil, Ruhr University Bochum, D-44780 Bochum, Germany
- Correspondence: ; Fax: +49-234-3214474
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